#How to test quantum gravity

[carionto]

Hyperbrake Racing

Everything in Human ships has a manual override. They love automating all processes and reduce any workload to nothing, but also have this compulsive need to be able to take direct control if so desired.

They also have emergency off switches for everything. Yes, including life support. Don't ask, you'll just get a variant of:

"But What If!?"

Obviously, this applies to things you should never under any circumstances shut down preemptively, such as a Hyperspace Jump.

The earliest space-faring civilizations quickly discovered that if a Hyperdrive has a power interruption even for a nano-second your atoms will get dispersed across a few light months. This is why all Hyperdrives have an internal chargeable uninterruptible power supply unit.

Humanity, however, did not allow "Not having any reason whatsoever" to stop them from figuring out a way. Utilizing their ridiculous quantum computer speed and the ability of their fusion reactors to charge a Hyperdrive mid-jump, and with an injection of a disgusting few million lines of hack code that manipulate all related pieces of hardware in just the most nauseating sequences, they created the Hyperbrake.

Also, not a metaphor - braking literally causes Humans to feel nauseous, sometimes throw up, rarely even pass out. Not a single volunteer crew member aboard joint vessels from any of the other Coalition species has dared to "test" what happens to them.

As with nearly all things Humans come across or invent, they will find a use for it should one not occur normally.

_____________________

Near Neptune

Daniel, Samantha, and Nicholas Schreier were three siblings ages 17, 19, and 20, respectively. Today they had "borrowed" their dad's General FordStar mark 980-MZ HaulerHound, a civilian grade transport typically used by small business owners. Dad, however, was an enthusiast, and had modified the "Hound Dog", as he calls it, with a military grade reactor and computer core. He's always been that guy who knows a guy who knows a guy who knows a guy who can get the thing legally enough.

There is a nearby research station that the kids often visit due to their mom working there, but today she was not. Instead, what they are doing, is racing against each other to set the best record. Well, technically the opposite of racing - coming to a halt.

Using the Hyperbrake, they are competing to see who can stop the closest to the stations outer point-defense range without entering it or you automatically lose. After Samantha's turn, they were suddenly contacted by the station. It was Yakovskii, one of mom's colleagues and a frequent guest at dad's barbecues, so they were on sorta good terms. Not by the tone voice coming through the comms rights now though:

"What in the Hell are you thinking!? At first I thought you were just messing around and accidentally did that, but TWICE now!?! I checked the trajectory, if you had stopped a half-second later, you would've ended up mere meters from Neptune's upper atmosphere! Did you account for the possible sudden gravitational pull? Can you maneuver that lumbering ship fast enough to not get pulled down? Not to mention Hyperbraking severely impairs your cognitive abilities for a moment? A moment that you need to be clearheaded for or risk DEATH!?!"

The three siblings could only hang their heads in shame and mutter out some weak apologies. After a moment of silence and reflection, Yakovskii speaks in a warmer tone:

*sigh* "Look, I understand it's a fancy new toy and you want to see what you can do. I get it, I really do. Me and my brother used to play vertical hockey the first time we got our hands on a surplus gravity field generator. But we first figured out how to make sure we didn't break our bones in case it failed. Seriously, never forget to consider your own safety first before you try out new things in a peaceful environment. You're not being chased by pirates or trying to avoid the law or whatever.

Take your time, pick a starting position that's further away and keeps Neptune and any of its moons to the side of the station, then aim for an area of space that only has the outer range of the defenses and empty space ahead from your point of view. And please set the regular Hyperjump destination within Sol, don't just pick a random place. The Hyperbrake sometimes loops in on itself and never executes the brake and can only be reset once out of Hyperspace. You don't want to get stuck in a pointless jump for hours do you?"

After this admonishment, the siblings apologized more energetically and took his advice to heart. They spent the next hour competing until all three were down to single meter differences and kinda got bored, so they docked at the station and hung out with the off-duty staff, played some poker, but then dad barged in and dragged them all home. They were not invited to the barbecue gatherings for two weeks, but only because mom told him to. Personally he was excited about all the data his kids had unknowingly given him with all their jumping and braking, a real stress test for his beautiful Hound Dog.

[mysticstronomy]

DOES QUANTUM GRAVITY EXIST??

Blog#389

Wednesday, April 3rd, 2024.

Welcome back,

All the fundamental forces of the universe are known to follow the laws of quantum mechanics, save one: gravity. Finding a way to fit gravity into quantum mechanics would bring scientists a giant leap closer to a “theory of everything” that could entirely explain the workings of the cosmos from first principles. A crucial first step in this quest to know whether gravity is quantum is to detect the long-postulated elementary particle of gravity, the graviton.

In search of the graviton, physicists are now turning to experiments involving microscopic superconductors, free-falling crystals and the afterglow of the big bang.

Quantum mechanics suggests everything is made of quanta, or packets of energy, that can behave like both a particle and a wave—for instance, quanta of light are called photons. Detecting gravitons, the hypothetical quanta of gravity, would prove gravity is quantum. The problem is that gravity is extraordinarily weak.

To directly observe the minuscule effects a graviton would have on matter, physicist Freeman Dyson famously noted, a graviton detector would have to be so massive that it collapses on itself to form a black hole.

“One of the issues with theories of quantum gravity is that their predictions are usually nearly impossible to experimentally test,” says quantum physicist Richard Norte of Delft University of Technology in the Netherlands. “This is the main reason why there exist so many competing theories and why we haven’t been successful in understanding how it actually works.”

In 2015, however, theoretical physicist James Quach, now at the University of Adelaide in Australia, suggested a way to detect gravitons by taking advantage of their quantum nature. Quantum mechanics suggests the universe is inherently fuzzy—for instance, one can never absolutely know a particle's position and momentum at the same time. One consequence of this uncertainty is that a vacuum is never completely empty, but instead buzzes with a “quantum foam” of so-called virtual particles that constantly pop in and out of existence.

These ghostly entities may be any kind of quanta, including gravitons.

Decades ago, scientists found that virtual particles can generate detectable forces. For example, the Casimir effect is the attraction or repulsion seen between two mirrors placed close together in vacuum. These reflective surfaces move due to the force generated by virtual photons winking in and out of existence.

Previous research suggested that superconductors might reflect gravitons more strongly than normal matter, so Quach calculated that looking for interactions between two thin superconducting sheets in vacuum could reveal a gravitational Casimir effect. The resulting force could be roughly 10 times stronger than that expected from the standard virtual-photon-based Casimir effect.

Recently, Norte and his colleagues developed a microchip to perform this experiment. This chip held two microscopic aluminum-coated plates that were cooled almost to absolute zero so that they became superconducting. One plate was attached to a movable mirror, and a laser was fired at that mirror. If the plates moved because of a gravitational Casimir effect, the frequency of light reflecting off the mirror would measurably shift. As detailed online July 20 in Physical Review Letters, the scientists failed to see any gravitational Casimir effect.

This null result does not necessarily rule out the existence of gravitons—and thus gravity’s quantum nature. Rather, it may simply mean that gravitons do not interact with superconductors as strongly as prior work estimated, says quantum physicist and Nobel laureate Frank Wilczek of the Massachusetts Institute of Technology, who did not participate in this study and was unsurprised by its null results. Even so, Quach says, this was a courageous attempt to detect gravitons.”

Originally published on https://www.scientificamerican.com

COMING UP!!

(Saturday, April 6th, 2024)

"HOW DOES A NEUTRON STAR FORM??"

[spacetimewithstuartgary]

NASA Aims to Fly First Quantum Sensor for Gravity Measurements

This mission will pave the way for groundbreaking observations of everything from petroleum reserves to global supplies of fresh water.

Researchers from NASA’s Jet Propulsion Laboratory in Southern California, private companies, and academic institutions are developing the first space-based quantum sensor for measuring gravity. Supported by NASA’s Earth Science Technology Office (ESTO), this mission will mark a first for quantum sensing and will pave the way for groundbreaking observations of everything from petroleum reserves to global supplies of fresh water.

Earth’s gravitational field is dynamic, changing each day as geologic processes redistribute mass across our planet’s surface. The greater the mass, the greater the gravity.

You wouldn’t notice these subtle changes in gravity as you go about your day, but with sensitive tools called gravity gradiometers, scientists can map the nuances of Earth’s gravitational field and correlate them to subterranean features like aquifers and mineral deposits. These gravity maps are essential for navigation, resource management, and national security.

“We could determine the mass of the Himalayas using atoms,” said Jason Hyon, chief technologist for Earth Science at JPL and director of JPL’s Quantum Space Innovation Center. Hyon and colleagues laid out the concepts behind their Quantum Gravity Gradiometer Pathfinder (QGGPf) instrument in a recent paper in EPJ Quantum Technology.

Gravity gradiometers track how fast an object in one location falls compared to an object falling just a short distance away. The difference in acceleration between these two free-falling objects, also known as test masses, corresponds to differences in gravitational strength. Test masses fall faster where gravity is stronger.

Cooled to a temperature near absolute zero, the particles in these clouds behave like waves. The quantum gravity gradiometer will measure the difference in acceleration between these matter waves to locate gravitational anomalies.

Using clouds of ultra-cold atoms as test masses is ideal for ensuring that space-based gravity measurements remain accurate over long periods of time, explained Sheng-wey Chiow, an experimental physicist at JPL. “With atoms, I can guarantee that every measurement will be the same. We are less sensitive to environmental effects.”

Using atoms as test masses also makes it possible to measure gravity with a compact instrument aboard a single spacecraft. QGGPf will be around 0.3 cubic yards (0.25 cubic meters) in volume and weigh only about 275 pounds (125 kilograms), smaller and lighter than traditional space-based gravity instruments.

Quantum sensors also have the potential for increased sensitivity. By some estimates, a science-grade quantum gravity gradiometer instrument could be as much as 10 times more sensitive at measuring gravity than classical sensors.

The main purpose of this technology validation mission, scheduled to launch near the end of the decade, will be to test a collection of novel technologies for manipulating interactions between light and matter at the atomic scale.

“No one has tried to fly one of these instruments yet,” said Ben Stray, a postdoctoral researcher at JPL. “We need to fly it so that we can figure out how well it will operate, and that will allow us to not only advance the quantum gravity gradiometer, but also quantum technology in general.”

This technology development project involves significant collaborations between NASA and small businesses. The team at JPL is working with AOSense and Infleqtion to advance the sensor head technology, while NASA’s Goddard Space Flight Center in Greenbelt, Maryland is working with Vector Atomic to advance the laser optical system.

Ultimately, the innovations achieved during this pathfinder mission could enhance our ability to study Earth, and our ability to understand distant planets and the role gravity plays in shaping the cosmos. “The QGGPf instrument will lead to planetary science applications and fundamental physics applications," said Hyon.

IMAGE: A map of Earth’s gravity. Red indicates areas of the world that exert greater gravitational pull, while blue indicates areas that exert less. A science-grade quantum gravity gradiometer could one day make maps like this with unprecedented accuracy. Credit: NASA

[talonabraxas]

Hyperdimensional Space Portal Talon Abraxas

Hyperspace theory (also called Superstring or Supergravity theory) begins with Einstein's General Relativity. In 1919, Theodr Kaluza, building upon relativity, made an astounding discovery: light and gravity can be unified and expressed with identical mathematics. This was the beginning of the unification of all physical laws, which is the ultimate goal of physics. There was only one catch. He needed an extra dimension. This fifth dimension, long recognized as mathematically plausible, had never before been seriously proposed as an actual component of reality. The usefulness of his theory was hard to deny; in five dimensions, there is "enough room" to accomplish the unification of gravity and light, which simply cannot be accomplished when trapped in four dimensional spacetime.

There is an obvious question to be asked at this point. "Where is the fifth dimension?" Kaluza's answer is clever, though suspiciously hard to test. He said that the fifth dimension is too small to see. The fifth dimension is contiguous with our four, but it is curled up, while the others are extended. To understand curled-up dimensions, imagine an ant living on a string (or a Linelander). For all its life, it is only aware of two directions: forward and backward. It lives in a one-dimensional universe. However, if you examine the string very closely, you find that it has a circumference; an extra dimension, curled up and wrapped back onto itself into a circle. If you could stretch this dimension, that is, make the circumference very large, the ant would be living on the two-dimensional surface of a cylinder. But when it's curled up, it effectively is undetectable by the ant, though it may serve as a medium for vibrations or other physical effects.

This Kaluza-Klein Theory (named after Kaluza and one of his students) was a curiosity for a while until people became disenchanted with its bizarre hypotheses and lack of concrete predictions. A common criticism was to ask why, if there could be one extra dimension, why not many? Just how many dimensions did this wacky theory have? For many years, people were content to leave gravity behind and work on examining the nature of subatomic matter via Quantum Mechanics.

Fortunately, in the 1980's, Kaluza-Klein came back with a vengence. The new wave of physicists supporting Hyperspace ("higher"-space) theories had an important element which was missing in the thirties: an exact prediction of the number of dimensions in our universe. By manipulating the formulae of Einstein, Riemann, and the like, they managed to unify all the forces of nature (gravity, the strong and weak nuclear forces, and the electromagnetic force, which includes light) in a single theory. How many dimensions did they need? Ten.

According to Hyperspace theory, each point in our four-dimensional universe conceals an additional six curled-up dimensions. The image at left provides insight on how this might be possible. Here we have a two-dimensional plane viewed at great magnification. At each point in the plane, there are the two curled-up dimensions of a sphere. In our universe, each point contains not a sphere, but a higher-dimensional object: a six-dimensional "Calabi-Yau Manifold." There is a very simple reason why we can't see these manifolds: they are less than 10^-33 centimeters across, much smaller than our most powerful microscopes can detect. Nonetheless, the movement of vibrating "strings" through these manifolds may be the source of all of physics.

[greatbigbellies]

2023 PREGNANCY KINK ADVENT CALENDAR (DAY 17)

McPreggo Mukbang Pt 3.

Pregnant with quads, overfull of amniotic fluid, and stuffed with multiple meals worth of fast food, Penelope wasn’t going to get anywhere quickly. Still, despite her heavily pregnant weight, she fought against gravity to try to stand up. She needed to test something.

She grunted deeply as she shifted forward onto her feet before slowly standing fully, her belly jutting out far in front of her. It hung so far forward that it completely blocked her view of the keyboard that was on her desk. She breathed heavily as she supported her extremely heavy belly with her hands, smiling halfheartedly at her camera as her chat exploded. She read none of it though as she instead relayed instructions to her viewers, now broaching the 1000’s.

“I’m going to turn by back to you guys, I need you to tell me if I look pregnant from the back,” she said, before rotating. She didn’t turn especially fast due to her weight, but the length of her belly still made it look like it swung quickly around. She faced away from her camera, holding her belly for about 5 seconds, before slowly turning back. She glanced at the flood of messages in the affirmative. Apparently her belly was so wide that you could clearly see the sides looming out, even from directly behind. She turned again, 90 degrees, to give her viewers a profile shot. “How overdue do I look right now?” she asked.

“Really really overdue.” “That’s the biggest tummy I’ve ever seen!” “Like you might fall over.” “Like a year pregnant.” “Penelope I think you might just be pregnant call it a hunch.”

Penelope read the chat, and caught a glimpse of herself in her streaming software. She was shocked that she could even stretch this far. She huffed as the strain of standing began to mount, and she dropped down into her chair again. The pood gamer chair creaked in protest under her immense weight, enough that she held her breath, afraid something would snap. When it didn’t she exhaled slowly and looked at the remaining nuggets. 12 measly chicken nuggets were all that remained of her mukbang, and she was ready to call it a day.

She reached for them before pausing, and looking at her monitor. She silently scrolled through the online menu before stopping on the nuggets, wanting to know what she was getting into. “Okay so, these are going to make the quadruplets I’m carrying 12% heavier, and… 24% more active. Good ones to end on I guess. I think 12% more weight and I would have fallen over. Lets see how they taste,” she ate a single regular nugget, and a single spicy one too. She chewed each thoroughly, really focusing on the flavors. “I mean, they’re chicken nuggets, they’re not the more complicated thing in the world. Still, they’re pretty good! I mean, the seasonings are nice and I will say that the spicy nuggets do have some heat. Nothing too intense but like… they’ll make your mouth tingle,” she said, before downing the other nuggets in rapid succession. Even after all of that food, and being so enormously pregnant, the nuggets were tasty enough that they disappeared quickly.

Penelope winced as one of the quantum babies in her womb began to squirm. Then the other, then the other, then all 4 were kicking and shifting enough to be visible from the outside. “Okay tha- UNF, that menu lied this is way more than 24% activity, they’re going crazy in there!” she complained, trying to shift in her chair but failing. “...and I feel more than 12% heavier, someone can’t do math,” she grumbled. Her chat pipped up again, reacting to the movement.

“Wow they’re really schmoovin’ huh?” “I’ve never seen it like that from the outside,” “Y’all seen the alien movies?”

“What does that feel like?”

Penelope panted slightly, the weight, and movement, and girth of her massive pregnant tummy was becoming overwhelming. “It feels like… I dunno, it’s just these heavy bodies moving around, independently of you. It’s really freaky, feeling something move inside you that ISN’T you,” she trailed off, staring down at her exposed, undulating belly.

She was massive. She was carrying four full sized eight pound babies inside of her, which were all moving, and even with the extra fluid from the polyhydramnios, still felt packed tight in her womb. Her belly skin was stretched tight, angry red stretchmarks adorned her curves. Her belly button poked out slightly, actually haven flattened with the addition of baby number 4 as she stretched too tight for a proper outie. Her tummy was wide, bowing out to the sides and brushing against the arms of her gamer chair. The entire thing was huge, heavy, and active. 

She just sat, silently, staring at herself. Her chat peppered her with messages, but she missed them all. She swept her hands over her tummy. She pulled them down to her underbelly, giving her tummy a slight lift before letting it drop. She took in the texture of her stretchmarks, and ran her thumb over her belly button. She felt a tiny foot kick into her palm.

It was finally clicking, somewhere in her, she liked it. Some part of her was thoroughly enjoying these sensations. She felt almost overstimulated, and yet somehow almost yearned for more. She felt one of her babies lurch in her, and her stomach, despite all she’d put in it today, growled. 

“So, uh, I’m going to take a little break, so use this time to get a snack or use the rest room. I think I’m going to… place a food delivery order.” she said, finally glancing up at her facecam. “I hear their milkshakes are very, very good,”

[religion-is-a-mental-illness]

By: Lee Myers

Published: Mar 16, 2013

1) Atheists Believe Everything Came From Nothing

Many theists believe there was once nothing, and then there was something—the universe—created by their god. And so they ask, “But if there is no god then how can something come from nothing?”

This question has been asked for thousands of years, but now Quantum physics has provided a basis for some atheists, such as Lawrence Krauss, to indeed believe the universe comes from “nothing.” But Krauss doesn’t speak for all atheists and he speaks of a very different kind of “nothing,” the kind where virtual particles are created from borrowed energy inside a vacuum. This is not even remotely close to what theists mean by the term “nothing.”

When asked about the universe, most atheists simply stop somewhere along the lines of “the evidence suggests the universe began expanding approximately 13.77 billion years ago.” Beyond that I’m fine with “I don’t know.” I don’t need to know. I do not believe the universe came from “nothing” in the way theists use the word or in the way Krauss uses the word. I don‘t think there’s enough evidence to reach a conclusion yet and I‘m fine with that. I’ve never met an atheist who believed everything comes from “nothing“ in the way theists use the word and in my experience, only a minority subscribe to the theory Krauss puts forward. Theists may believe the universe sprang from nothing, but they then have the burden of proving there was ever “nothing” and that “something” requires any gods at all.

2) Atheists Have No Morals

Humans are social beings, and as such we have morals. Some theists say atheists have no reason to be moral since we don’t believe in a god to instruct or punish us. This claim seems rather disingenuous when one considers that most theists who say this wouldn’t become immoral deviants overnight if they suddenly stopped believing in a god.

Studies have shown our morals are a product of multiple factors. The Milgram experiment shows authority plays a major role. The Stanford prison experiment showed the same, but also displayed the role of social hierarchy. The “good or evil” puppet test for babies suggests we are all born with a basic sense of fairness, justice, and unfortunately, bigotry. Human morality is too complex to be explained by religion or lack of it.

Millions of atheists across the globe live moral lives every day. Some don’t. Neither do some believers. There are atheist charities and atheist criminals. There are religious charities and religious hate groups. Religious people and atheists can both behave morally or immorally because of—or wholly independent of—their religious beliefs. One doesn’t necessarily lead to the other. Studies have shown the basis of human morality is present even before we’re exposed to religion.

3) Atheists Have No Meaning of Life

Even if humanity survives the next 5 billion years on this planet, the sun will balloon into a red giant, boil and possibly devour the earth before exploding and blasting out through the cosmos. The universe will continue to expand at an increasing rate, and eventually the force of gravity will be too weak for any new stars or planets to form. The universe will whither and die.

Some theists consider this and think without belief in an afterlife, nothing really matters in this life. Believing in an afterlife can influence one’s meaning of life, but a meaning of life doesn’t require belief in an afterlife. Some theists refer to Nietzsche’s nihilism as if Nietzsche were the be-all and end-all of existentialist philosophy. But humans generally define our meaning in the moments we enjoy and the goals we set. This was probably best articulated by Albert Camus in The Myth of Sisyphus.

I enjoy every moment I spend with my daughter, and one of my goals is to be a good father. I enjoy art, and one of my goals is to read, hear and see more of it. I like a large, hot cup of coffee while watching the dim glow of morning just before dawn. I love the serenity of canoeing on a sunny day and the soft crunch of fresh snow beneath my feet. I enjoy my friends and my family. Atheism does give life meaning because as an atheist, I understand this is the only life I’ve got.

4) There Are No Atheists in Foxholes

Yes there are. They even have a website. Nonetheless there persists among some this belief that atheism is generally disingenuous and that everyone cries out to “God” in times of need. This claim highlights a conflicting epistemology between the theist who is basing beliefs in part on fear and need, and the those of us who determine beliefs based on facts and evidence.

Their assumption also implies that when a theist cries out “Oh God,” they are literally trying to talk to “God.” I have several religious family and friends who say “Oh God” in all sorts of scenarios but are rarely actually trying to carry on a conversation with The Almighty. Even a theist saying “Oh God” in a foxhole is most likely not actually expecting divine intervention. The phrase is generally used in the same way as “Oh Shit,” which generally doesn’t involve any reference to actual shit. Even so, there are millions of people who’ve encountered life threatening situations and didn’t cry out about god, shit or anything else.

5) Atheists Just Hate God

About as much as we hate unicorns. Theists tend to make this claim when atheists assert moral opinions about supposed deeds of their deity. “How can you have opinions about something you don’t believe in?” The same way we form opinions about Darth Vader, Willy Wonka or the Wicked Witch of the West—according to their role within the story. It doesn’t matter if the story involves a Sith killing all the Jedi kids or a god killing a nation’s first born.

Just repeating the claim back usually gets the point across. Do Christians “hate” Allah? Do Muslims “hate” Jesus? Do Jews “hate” the FSM? Not believing in a particular religion is not dependent on a negative opinion of that religion’s deity or messiah figure. It’s simply the result of not being convinced because the burden of proof has not been met. I personally think Buddha and Lao Tzu both had great things to say, but I’m not a Buddhist or a Taoist.

6) Atheists Just Don’t Want to Submit to God

Well, one would first need to provide reason for believing there is anything to submit to. Lacking belief in deities doesn’t mean one doesn’t want to submit to what they don’t believe in. Like number 5, the point can be made rather easily by simply repeating this back to the theist. Does the Christian lack belief in Allah just because she doesn’t want to wear a hijab? Do non Catholics lack belief in Catholicism simply because they don’t want to submit to the Pope? Do Muslims lack belief Jesus was the embodiment of “God” simply because they want to continue justifying child marriages with the actions of their so-called prophet?

7) Atheists Are Angry

There once was a time when challenging religion was considered taboo. Some would like to hold on to that standard to save their religion from scrutiny. Those days are over, but that doesn‘t mean being skeptical of religion means skeptics are angry.

Being confrontational does not equate to anger. If someone told you Elvis was spotted buying T-shirts at K-Mart, their claims would be analyzed, scrutinized, debunked and in most cases, outright laughed at. I see no reason why it should be any different for religious claims.

8) Atheists Are Responsible for the Worst Atrocities in History

Stalin, Pol Pot and Mao were all atheists, so atheism must be responsible for the mass executions during said reigns—or so the accusation goes. This statement is usually a retort to blaming Christianity for the Crusades or Islam for terrorism. The fact of the matter is there have been Christians, atheists, Muslims and many others of different beliefs and non beliefs who have committed multiple atrocities throughout history. But there have also been some of the kindest deeds in history performed by people of all kinds of belief and non belief.

Stalin, Pol Pot and Mao did not execute people in the name of atheism, but rather for simply not submitting to them as if they were gods themselves. There is a long list of atheist politicians who never committed atrocities. Claiming atheism would lead to disastrous atrocities like those witnessed in the early Soviet Union is a hasty generalization fallacy which ignores all the good deeds of decent atheist politicians throughout time.

9) Atheists Are Guilty of “Scientism”

It must be difficult holding beliefs which cannot be justified with evidence. This leads some theists to conclude atheists all subscribe to “scientism.” This term is meant as an insult against skeptics for daring to ask for evidence when confronted with extraordinary claims.

Scientism is a philosophy which holds that science is the ultimate truth, and that science is the only way to truth. But preferring science to superstition doesn’t mean science is always correct. Scientists are humans and can make mistakes like anyone else. However, the methodology of science does work. That doesn’t mean science is the only way to truth. It just means it’s an effective method of attaining natural truths.

Many atheists are equally skeptical of science and religion. My first assignment in my college statistics class was to find three examples of misused data in the media. This same task had been given to each class for over a decade and no two people ever turned in the same three examples. I have also studied philosophy, including philosophy of science, and so I understand science can be wrong. I have yet to meet an atheist who believes scientists are infallible.

10) Atheists Are All Rational and Logical

This is one I hear mostly from other atheists. Some atheists like to consider themselves more rational than theists and ask why we should call ourselves atheists at all, as opposed to calling ourselves rationalists or some other such term.

But all atheists are not rational. Atheism is simply the lack of belief in deities. There are atheists who believe in homeopathy, ancient aliens, 911 conspiracy theories and a host of other completely irrational ideas unsupported by any stretch of logic. Just because someone arrived at the rational non belief in deities does not mean they are rational about everything else.

[frank-olivier]

Quantum Complexity and the Event Horizon: A New Perspective

Computational complexity has become an intriguing concept in black hole physics, offering new insights into the nature of black holes and their interiors. In computational theory, complexity refers to the resources required to solve a problem, such as time or computational steps. When applied to quantum systems, it specifically looks at how many quantum operations (or gates) are needed to transform one quantum state into another. This concept becomes particularly interesting when examining black holes.

Black holes have long been a subject of fascination due to their mysterious nature and the information paradox. The paradox arises from the apparent loss of information when matter falls into a black hole, seemingly violating the principle of information conservation in quantum mechanics. Recent theoretical developments suggest that the complexity of a quantum state can be associated with the geometric properties of a black hole's interior. The idea is that as a black hole evolves, its interior volume grows, which can be thought of as an increase in the complexity of the quantum state representing the black hole.

This perspective provides a new way to think about what happens inside a black hole. Instead of being a place where nothing escapes, it becomes a region where processes are highly complex. This complexity might hold the key to understanding how information is stored and potentially retrieved from black holes. Traditionally, the event horizon of a black hole is seen as a boundary beyond which nothing can return. However, by considering computational complexity, this view is nuanced. The horizon acts more like a filter or censor that prevents an outside observer from easily accessing the information within. It's not that information cannot escape; rather, decoding or accessing it requires immense computational resources.

The introduction of complexity also touches on fundamental principles like the quantum extended Church-Turing Thesis, which posits that any physical process can be efficiently simulated by a quantum computer. In the context of black holes, this principle suggests that while information might not be lost, simulating or retrieving it is computationally prohibitive for an observer outside the horizon.

These insights have profound implications for our understanding of both black holes and fundamental physics. They suggest new ways to reconcile general relativity with quantum mechanics and provide potential pathways for resolving longstanding paradoxes. Research in this area is ongoing, with physicists exploring how these concepts can be tested or further developed through theoretical models and potentially even experimental evidence in quantum computing and gravitational physics.

Leonard Susskind: Quantum Complexity - Quantum PCP, Area Laws, and Quantum Gravity (Simons Institute, March 2024)

Sunday, September 22, 2024

[startswithabang]

Do gravitational waves exhibit wave-particle duality?

Gravitational waves are, unsurprisingly, wave-like.

But if the Universe, and gravity, are quantum in nature, then they should have particle-like behavior, too.

Here's how we might test that idea.

[noneofthisisreal]

(via If the Universe Is a Hologram, This Long-Forgotten Math Could Decode It | Quanta Magazine)

To get a sense of how it works, imagine you have a two-dimensional sheet of metal wrapped into a sphere, like a hollow aluminum ball (it remains 2D in the sense that you can locate any point on it with a longitude and a latitude). The sheet hosts quantum particles, which can be thought of as tiny ripples in media known as quantum fields. These fields and their ripples obey complicated but well-tested mathematical rules, known as quantum field theory. In this case, the ripples follow a symmetric theory known as a conformal field theory or CFT.

The big surprise, which Maldacena and others have now explored in thousands of papers, is that this two-dimensional surface is mathematically equivalent, or “dual,” to the three-dimensional volume it encloses, called the bulk. The duality gives rise to an entire toy universe. Certain collections of ripples on the 2D boundary might represent a 3D star in the bulk, for instance, and others a bulk planet.

The bulk universe differs from ours in that its space has an intrinsically negative energy, making it “anti-de Sitter” or AdS space. But other than that, it looks a lot like our home; it’s a malleable space-time fabric whose curves produce gravity. The AdS/CFT correspondence opens up the tantalizing possibility that physicists could do an end run around physics they don’t understand (quantum gravity in the bulk) by using only physics they do understand (quantum field theory).

[nina208-journey-to-consistency]

oppenheimer thoughts (spoilers!)

initial thoughts (left the theater 2 hrs ago, these are v rough impressions):

- holy fuck that was good

- the scientists i studied are all here! go quantum mechanics :)

- the subtle acting all throughout the movie was tremendous

- it is such a beautifully shot film, love the color scheme decisions

- i wish some of the characters (the women) had more to do almost (it seems as if a lot of characters didn’t get a lot of dialogue and we don’t know much about them.)

- cillian murphy. that’s it, cillian murphy (amazing)

- i didn’t really feel like there was a specific heart to this movie, but more a weight and a ponderous thoughtfulness that is presented to the viewer due to the gravity of the situation

- i loved how it didn’t really paint oppenheimer as a “great man”. walking out of the theater it seemed like the movie was more about the phrase “actions have consequences” and how diff people lived with the impact of that

- the sound design and score of this movie is one of my favorite things

- i also like that it humanized science, almost. like, giant decisions were being undertaken by people who, at the end of the day, were uncertain about stuff but had to make decisions anyway. and highlighted the difference and common ground between politics and science (and how both can really affect people’s lives). as a scientist myself it made me think more about the actual impact of my work and the value of doing your due diligence (triple checking stuff, thinking about who you will serve, and what potential ripple effects there are) 

(but also that the decision had a catastrophic human toll. throughout this entire movie i couldn’t forget the fact that so many people’s lives and health (EVEN TODAY) are so horribly impacted by the atomic bomb. the movie seemed like it wanted to make the viewer confront that too which was good. but truly not enough. they just glossed over how los alamos was created as well as the impact in japan)

- it made me feel like i was at the trinity test site (the silence right when i didn’t expect it and the insane visuals made my jaw drop. then the reverberations i knew were coming still made me jump)

this is a movie i need to watch again and discuss before adding more detailed thoughts. had an incredible time :)

[defat1]

Don't mind me, I'm just going to vent a bit about being 'Gifted'

I'm watching a video on macrouniversal structures like galactic voids and filaments right now, and once again I'm regretting my absolute lack of mathematical ability to pursue a life of science. I look at stuff like this and quantum mechanics and I can't help but feel like I'm one conceptual step away from a world shattering realization. Crazy shit like, gravity not being a fundamental force, but instead an emergent property of the way mass interacts with space and tied to c in a way I dont have the words or math to describe. Or like, trying to unify quantum and traditional physics, or solving whatever the heck dark matter really is because my subconscious doesn't buy 'intangible, non-interacting mass that adds extra gravity to already gravitational macrosystems' as an explanation.

Then I have to remind myself that there’s almost certainly been a thousand other people smarter than me who already thought of it, made the math for it, tested it and dismissed the idea. It's very humbling, but also frustrating. I'm not a genius, but I know I'm well above average intelligence, and that margin feels like a curse sometimes even though I cherish it. I can't know for sure if my thoughts are just the idle imagination of a worldbuilder looking for 'just so' stories to patch the great mysteries of physics, or if I'm Issac Newton questioning why apples fall, but instead of working it out, shrugging the saying I'm sure someone else is working on it.

I suffer from a cocktail of invisible disabilities, like many people I know. The usual suspects of learning and social neurodivergence, depression, anxiety, and for a bit of spice, Sighted non-24. I was told over and over as a kid, as many like me were, that I was Destined for Great Things, that i had Potential and not to waste it, that i could go to school, get a master's, and probably land a professorship somewhere. Nobody told me how little society cared for hidden disabilities. There are many millions of people far more gifted than I ever was, and I sometimes wonder how many of them fell through the cracks like me, and where we might be if we'd all been told; or better, actually taught; to help even complete strangers you share nothing but humanity with, because you never know what they would be capable of if they didn't have to worry about their basic needs.

[xtruss]

A New Map of the Universe, Painted With Cosmic Neutrinos

Physicists finally know where at least some of these high-energy particles come from, which helps make the neutrinos useful for exploring fundamental physics.

— Thomas Lewton, Contributing Writer | June 29th, 2023

Since 2012, the IceCube Neutrino Observatory at the South Pole has detected a dozen or so cosmic neutrinos each year. Kristina Armitage/Quanta Magazine; images courtesy of IceCube Collaboration

Of the 100 trillion neutrinos that pass through you every second, most come from the sun or Earth’s atmosphere. But a smattering of the particles — those moving much faster than the rest — traveled here from powerful sources farther away. For decades, astrophysicists have sought the origin of these “cosmic” neutrinos. Now, the IceCube Neutrino Observatory has finally collected enough of them to reveal telltale patterns in where they’re coming from.

In a paper published today in Science, the team revealed the first map of the Milky Way in neutrinos. (Usually our galaxy is mapped out with photons, particles of light.) The new map shows a diffuse haze of cosmic neutrinos emanating from throughout the Milky Way, but strangely, no individual sources stand out. “It’s a mystery,” said Francis Halzen, who leads IceCube.

The results follow an IceCube study from last fall, also in Science, that was the first to connect cosmic neutrinos to an individual source. It showed that a large chunk of the cosmic neutrinos detected so far by the observatory have come from the heart of an “active” galaxy called NGC 1068. In the galaxy’s glowing core, matter spirals into a central supermassive black hole, somehow making cosmic neutrinos in the process.

“It’s really gratifying,” said Kate Scholberg, a neutrino physicist at Duke University who wasn’t involved in the research. “They’ve actually identified a galaxy. This is the kind of thing the entire neutrino astronomy community has been trying to do for forever.”

Pinpointing cosmic neutrino sources opens up the possibility of using the particles as a new probe of fundamental physics. Researchers have shown that the neutrinos can be used to open cracks in the reigning Standard Model of particle physics and even test quantum descriptions of gravity.

Yet identifying the origin of at least some cosmic neutrinos is only a first step. Little is known about how the activity around some supermassive black holes generates these particles, and so far the evidence points to multiple processes or circumstances.

Merrill Sherman/Quanta Magazine; images courtesy of IceCube Collaboration

Long-Sought Origin

Abundant as they are, neutrinos usually zip through Earth without leaving a trace; a magnificently huge detector had to be built to detect enough of them to perceive patterns in the directions they arrive from. IceCube, built 12 years ago, consists of kilometer-long strings of detectors bored deep into the Antarctic ice. Each year, IceCube detects a dozen or so cosmic neutrinos with such high energy that they clearly stand out against a haze of atmospheric and solar neutrinos. More sophisticated analyses can tease out additional candidate cosmic neutrinos from the rest of the data.

Astrophysicists know that such energetic neutrinos could only arise when fast-moving atomic nuclei, known as cosmic rays, collide with material somewhere in space. And very few places in the universe have magnetic fields strong enough to whip cosmic rays up to sufficient energies. Gamma-ray bursts, ultrabright flashes of light that occur when some stars go supernova or when neutron stars spiral into each other, were long thought one of the most plausible options. The only real alternative was active galactic nuclei, or AGNs —galaxies whose central supermassive black holes spew out particles and radiation as matter falls in.

The gamma-ray-burst theory lost ground in 2012, when astrophysicists realized that if these bright bursts were responsible, we would expect to see many more cosmic neutrinos than we do. Still, the dispute was far from settled.

Then, in 2016, IceCube began sending out alerts every time they detected a cosmic neutrino, prompting other astronomers to train telescopes in the direction it came from. The following September, they tentatively matched up a cosmic neutrino with an active galaxy called TXS 0506+056, or TXS for short, that was emitting flares of X-rays and gamma rays at the same time. “That certainly sparked a lot of interest,” said Marcos Santander, an IceCube collaborator at the University of Alabama.

More and more cosmic neutrinos were collected, and another patch of sky began to stand out against the background of atmospheric neutrinos. In the middle of this patch is the nearby active galaxy NGC 1068. IceCube’s recent analysis shows that this correlation almost certainly equals causation. As part of the analysis, IceCube scientists recalibrated their telescope and used artificial intelligence to better understand its sensitivity to different patches of sky. They found that there’s less than a 1-in-100,000 chance that the abundance of neutrinos coming from the direction of NGC 1068 is a random fluctuation.

Statistical certainty that TXS is a cosmic neutrino source isn’t far behind, and in September, IceCube recorded a neutrino probably from the vicinity of TXS that hasn’t been analyzed yet.

“We were partially blind; it’s like we’ve turned the focus on,” said Halzen. “The race was between gamma-ray bursts and active galaxies. That race has been decided.”

An illustration of IceCube’s interior during a detection. When a neutrino interacts with molecules in the Antarctic ice, it produces secondary particles that leave a trace of blue light as they travel through the detector. Nicolle R. Fuller/NSF/IceCube

The Physical Mechanism

These two AGNs appear to be the brightest neutrino sources in the sky, yet, puzzlingly, they’re very different. TXS is a type of AGN known as a blazar: It shoots a jet of high-energy radiation directly toward Earth. Yet we see no such jet pointing our way from NGC 1068. This suggests that different mechanisms in the heart of active galaxies could give rise to cosmic neutrinos. “The sources seem to be more diverse,” said Julia Tjus, a theoretical astrophysicist at Ruhr University Bochum in Germany and a member of IceCube.

Halzen suspects there is some material surrounding the active core in NGC 1068 that blocks the emission of gamma rays as neutrinos are produced. But the precise mechanism is anyone’s guess. “We know very little about the cores of active galaxies because they are too complicated,” he said.

The cosmic neutrinos originating in the Milky Way muddle things further. There are no obvious sources of such high-energy particles in our galaxy — in particular, no active galactic nucleus. Our galaxy’s core hasn’t been bustling for millions of years.

Halzen speculates that these neutrinos come from cosmic rays produced in an earlier, active phase of our galaxy. “We always forget that we are looking at one moment in time,” he said. “The accelerators that made these cosmic rays may have made them millions of years ago.”

What stands out in the new image of the sky is the intense brightness of sources like NGC 1068 and TXS. The Milky Way, filled with nearby stars and hot gas, outshines all other galaxies when astronomers look with photons. But when it’s viewed in neutrinos, “the amazing thing is we can barely see our galaxy,” said Halzen. “The sky is dominated by extragalactic sources.”

Setting the Milky Way mystery aside, astrophysicists want to use the farther, brighter sources to study dark matter, quantum gravity and new theories of neutrino behavior.

IceCube has detected dozens of neutrinos coming from NGC 1068, also known as Messier 77 — an active galaxy located 47 million light-years away. The well-studied galaxy, imaged here by the Hubble Space Telescope, is visible with large binoculars. NASA/ESA/A. van der Hoeven

Probing Fundamental Physics

Neutrinos offer rare clues that a more complete theory of particles must supersede the 50-year-old set of equations known as the Standard Model. This model describes elementary particles and forces with near-perfect precision, but it errs when it comes to neutrinos: It predicts that the neutral particles are massless, but they aren’t — not quite.

Physicists discovered in 1998 that neutrinos can shape-shift between their three different types; an electron neutrino emitted by the sun can turn into a muon neutrino by the time it reaches Earth, for example. And in order to shape-shift, neutrinos must have mass — the oscillations only make sense if each neutrino species is a quantum mixture of three different (all very tiny) masses.

Dozens of experiments have allowed particle physicists to gradually build up a picture of the oscillation patterns of various neutrinos — solar, atmospheric, laboratory-made. But cosmic neutrinos originating from AGNs offer a look at the particles’ oscillatory behavior across vastly bigger distances and energies. This makes them “a very sensitive probe to physics that is beyond the Standard Model,” said Carlos Argüelles–Delgado, a neutrino physicist at Harvard University who is also part of the sprawling IceCube collaboration.

Cosmic neutrino sources are so far away that the neutrino oscillations should get blurred out — wherever astrophysicists look, they expect to see a constant fraction of each of the three neutrino types. Any fluctuation in these fractions would indicate that neutrino oscillation models need rethinking.

Another possibility is that cosmic neutrinos interact with dark matter as they travel, as predicted by many dark-sector models. These models propose that the universe’s invisible matter consists of multiple types of nonluminous particles. Interactions with these dark matter particles would scatter neutrinos with specific energies and create a gap in the spectrum of cosmic neutrinos that we see.

Or the quantum structure of space-time itself can drag on the neutrinos, slowing them down. A group based in Italy recently argued in Nature Astronomy that IceCube data shows hints of this happening, but other physicists have been skeptical of these claims.

Effects such as these would be minute, but intergalactic distances could magnify them to detectable levels. “That’s definitely something that’s worth exploring,” said Scholberg.

Already, Argüelles–Delgado and collaborators have used the diffuse background of cosmic neutrinos — rather than specific sources like NGC 1068 — to look for evidence of the quantum structure of space-time. As they reported in Nature Physics in October, they didn’t find anything, but their search was hampered by the difficulty of distinguishing the third variety of neutrino — tau — from an electron neutrino in the IceCube detector. What’s needed is “better particle identification,” said co-author Teppei Katori of King’s College London. Research is underway to disentangle the two types.

Katori says knowing specific locations and mechanisms of cosmic neutrino sources would offer a “big jump” in the sensitivity of these searches for new physics. The exact fraction of each neutrino type depends on the source model, and the most popular models, by chance, predict that equal numbers of the three neutrino species will arrive on Earth. But cosmic neutrinos are still so poorly understood that any observed imbalance in the fractions of the three types could be misinterpreted. The result could be a consequence of quantum gravity, dark matter or a broken neutrino oscillation model — or just the still-blurry physics of cosmic neutrino production. (However, some ratios would be a “smoking gun” signature of new physics, said Argüelles–Delgado.)

Ultimately, we need to detect many more cosmic neutrinos, Katori said. And it looks as though we will. IceCube is being upgraded and expanded to 10 cubic kilometers over the next few years, and in October, a neutrino detector under Lake Baikal in Siberia posted its first observation of cosmic neutrinos from TXS.

And deep in the Mediterranean, dozens of strings of neutrino detectors collectively called KM3NeT are being fastened on the seafloor by a robot submersible to offer a complementary view of the cosmic-neutrino sky. “The pressures are enormous; the sea is very unforgiving,” said Paschal Coyle, a director of research at the Marseille Particle Physics Center and the experiment’s spokesperson. But “we need more telescopes scrutinizing the sky and more shared observations, which is coming now.”

[mysticstronomy]

HOW MANY DIMENSIONS EXIST??

Blog#347

Wednesday, November 8th, 2023

Welcome back,

The world as we know it has three dimensions of space—length, width and depth—and one dimension of time. But there’s the mind-bending possibility that many more dimensions exist out there. According to string theory, one of the leading physics model of the last half century, the universe operates with 10 dimensions.

But that raises a big question: If there are 10 dimensions, then why don’t we experience all of them or haven’t detected them? Lisa Grossman at ScienceNews reports that a new paper suggests an answer, showing that those dimensions are so tiny and so fleeting that we currently can’t detect them.

It’s difficult to completely explain the mathematics behind string theory without putting on a graduate seminar or two, but in essence dimensions five through ten have to do with possibility and include all possible futures and all possible pasts including realities with a totally different physics than those in our universe.

If two protons smash together at high enough speeds, they have the ability to create a tiny black hole that would exist for just a fraction of a second before disappearing, according to a new study, which hasn't been peer-reviewed, on the preprint server arXiv.org. The collision would open up a little bubble of interdimensional space where the laws of physics are different than ours, leading to an event known as vacuum decay. In quantum physics, vacuum decay implies that if the interdimensional space was large enough, we’d be toast.

With enough gravity to interact with our world, the newly formed “Cosmic Death Bubble” would grow at the speed of light, rapidly change the physics of our universe, render it uninhabitable and effectively zap us out of existence.

“If you’re standing nearby when the bubble starts to expand, you don’t see it coming,” the study’s co-author, physicist Katie Mack of North Carolina State University, tells Grossman. “If it’s coming at you from below, your feet stop existing before your mind realizes that.”

Ultrahigh energy cosmic rays are bashing into each other all the time with enough energy to start this process. If extra dimensions were large enough to allow the death bubble to form, the researchers found, it would have happened thousands of times already. The fact that we still exist is one circumstantial piece of evidence that other dimensions are ultra-tiny. The team calculated that they must be smaller than 16 nanometers, too small for their gravity to influence much in our world and hundreds of times smaller than previous calculations, Grossman reports.

The new study comes on the tail of another study about extra dimensions published in the Journal of Cosmology and Astroparticle Physics published in July. Mara Johnson-Groh at LiveScience reports that one of the big questions in physics is why the expansion of the universe is accelerating. One theory is that gravity is leaking out of our universe into other dimensions. To test this idea, researchers looked at data from recently discovered gravitational waves.

our universe was leaking gravity through these other dimensions, the researchers reasoned, then the gravitational waves would be weaker than expected after traveling across the universe.

But the researchers found they didn’t lose any energy on their long journey, meaning other dimensions either don’t exist or are so tiny they don’t affect gravity very much, if at all.

“General relativity says gravity should be working in three dimensions, and [the results] show that that’s what we see,” physicist Kris Pardo of Princeton, lead author of the July study, tells Johnson-Groh. The latest study also concludes that the size of extra dimensions is so small that it precludes many theories about gravity leaking out of our universe.

Originally published on www.smithsonianmag.com

COMING UP!!

(Saturday, November 11th, 2023)

"WHAT IS THE FURTHEST THING WE CAN SEE IN SPACE??"

[spacetimewithstuartgary]

Black holes Beyond the singularity

“Hic sunt leones,” remarks Stefano Liberati, one of the authors of the paper and director of IFPU. The phrase refers to the hypothetical singularity predicted at the center of standard black holes — those described by solutions to Einstein’s field equations. To understand what this means, a brief historical recap is helpful.

In 1915, Einstein published his seminal work on general relativity. Just a year later, German physicist Karl Schwarzschild found an exact solution to those equations, which implied the existence of extreme objects now known as black holes. These are objects with mass so concentrated that nothing — not even light — can escape their gravitational pull, hence the term “black”.

From the beginning, however, problematic aspects emerged and sparked a decades-long debate. In the 1960s, it became clear that spacetime curvature becomes truly infinite at the center of a black hole: a singularity where the laws of physics — or so it seems — cease to apply. If this singularity were real, rather than just a mathematical artifact, it would imply that general relativity breaks down under extreme conditions. For much of the scientific community, invoking the term “singularity” has become a kind of white flag: it signals that we simply don’t know what happens in that region.

Despite the ongoing debate around singularities, scientific evidence for the existence of black holes has continued to grow since the 1970s, culminating in major milestones such as the 2017 and 2020 Nobel Prizes in Physics. Key moments include the first detection of gravitational waves in 2015 — revealing the merger of two black holes — and the extraordinary images captured by the Event Horizon Telescope (EHT) in 2019 and 2022. Yet none of these observations has so far provided definitive answers about the nature of singularities.

Unknowable territory

And this brings us back to the “leones” Liberati refers to: we can describe black hole physics only up to a certain distance from the center. Beyond that lies mystery — an unacceptable situation for science. This is why researchers have long been seeking a new paradigm, one in which the singularity is “healed” by quantum effects that gravity must exhibit under such extreme conditions. This naturally leads to models of black holes without singularities, like those explored in the work of Liberati and his collaborators.

One of the interesting aspects of the new paper is its collaborative origin. It is neither the work of a single research group nor a traditional review article. “It’s something more,” explains Liberati. “It emerged from a set of discussions among leading experts in the field — theorists and phenomenologists, junior and senior researchers — all brought together during a dedicated IFPU workshop. The paper is a synthesis of the ideas presented and debated in the sessions, which roughly correspond to the structure of the article itself.” According to Liberati, the added value lies in the conversation itself: “On several topics, participants had initially divergent views — and some ended the sessions with at least partially changed opinions.”

Two non-singular alternatives

During that meeting, three main black hole models were outlined: the standard black hole predicted by classical general relativity, with both a singularity and an event horizon; the regular black hole, which eliminates the singularity but retains the horizon; and the black hole mimicker, which reproduces the external features of a black hole but has neither a singularity nor an event horizon.

The paper also describes how regular black holes and mimickers might form, how they could possibly transform into one another, and, most importantly, what kind of observational tests might one day distinguish them from standard black holes.

While the observations collected so far have been groundbreaking, they don’t tell us everything. Since 2015, we’ve detected gravitational waves from black hole mergers and obtained images of the shadows of two black holes: M87* and Sagittarius A*. But these observations focus only on the outside — they provide no insight into whether a singularity lies at the center.

“But all is not lost,” says Liberati. “Regular black holes, and especially mimickers, are never exactly identical to standard black holes — not even outside the horizon. So observations that probe these regions could, indirectly, tell us something about their internal structure.”

To do so, we will need to measure subtle deviations from the predictions of Einstein’s theory, using increasingly sophisticated instruments and different observational channels. For example, in the case of mimickers, high-resolution imaging by the Event Horizon Telescope could reveal unexpected details in the light bent around these objects — such as more complex photon rings. Gravitational waves might show subtle anomalies compatible with non-classical spacetime geometries. And thermal radiation from the surface of a horizonless object — like a mimicker — could offer another promising clue.

A promising future

Current knowledge is not yet sufficient to determine exactly what kind of perturbations we should be looking for, or how strong they might be. However, significant advances in theoretical understanding and numerical simulations are expected in the coming years. These will lay the groundwork for new observational tools, designed specifically with alternative models in mind. Just as happened with gravitational waves, theory will guide observation — and then observation will refine theory, perhaps even ruling out certain hypotheses.

This line of research holds enormous promise: it could help lead to the development of a quantum theory of gravity, a bridge between general relativity — which describes the universe on large scales — and quantum mechanics, which governs the subatomic world.

“What lies ahead for gravity research,” concludes Liberati, “is a truly exciting time. We are entering an era where a vast and unexplored landscape is opening up before us.”

IMAGE: Singular black hole and non-singular alternatives  Credit Sissa Medialab. Background image sourced from ESO/Cambridge Astronomical Survey Unit

[govindhtech]

Quantum ML Sheds Quantum black hole information retrieval

Quantum Black Hole

Black hole physics and quantum machine learning intersect in a study on information retrieval constraints.

A recent theoretical work on arXiv relates machine learning's “double descent” phenomenon to black hole mathematical evaporation. The study provides a shared architecture for data recovery in both systems.

The study models the Hawking radiation process as a quantum linear regression problem and finds that the Page time, at which radiation begins to reveal internal Quantum Black Hole information, is the interpolation threshold where test error significantly spikes in overparameterized learning models. Quantum information theory and random matrix analysis make black hole information recovery a high-dimensional learning problem. Importantly, the report makes no new experimental proposals or claims black holes can compute.

Conceptual bridge The Page curve from quantum black hole physics and the twofold descent curve from statistical learning are intimately linked in this study. Both theories explain information accessibility changes. Page time in black holes measures how much information is in the outer radiation relative to the Quantum Black Hole interior. This is significant because Hawking radiation information begins to emerge, like a phase change. Machine learning's interpolation threshold determines if a model can fit training data perfectly. Even when the model is overfit, its performance can improve after this threshold.

Spectral analysis of high-dimensional systems is needed to relate these events. Quantum black hole radiation shape and rank are measured by Marchenko-Pastur distribution. Massive random matrices stretch or compress dimensions. This distribution is needed to understand sparse data-trained machine learning model generalisation. According to their model, radiation dimensionality is like learning model parameters and Quantum Black Hole microstates are proportional to dataset size.

Label Prediction from Features The paper offers a quantum learning problem to learn the black hole's intrinsic states as a model learns labels from features. visible radiation. We consider Hawking radiation information retrieval supervised learning. They demonstrate in their quantum regression model that the test error diverges at the Page time, which is identical to the classical double descent error spike at the interpolation threshold. The test error falling on each side of this peak shows geometric or inversion symmetry in machine learning systems.

When model capacity equals data size, performance is worst; when capacity is significantly smaller or larger, performance increases. Black hole evaporation behaves similarly when the radiation's entropy matches the surviving black hole's, making information the least recoverable at Page time. A “quantum phase transition” in information retrieval occurs when the prediction error variance, which measures model sensitivity, diverges at Page time. The radiation subsystem alone can retrieve all Quantum Black Hole inner information after the Page time, when the radiation space becomes “overcomplete.”

Techniques and Frameworks Density matrices that encode probabilistic quantum states simulate the Quantum Black Hole and its radiation as a quantum system to get their results. Evaporation is linked to supervised learning by evaluating these matrices' regression behaviour. Formulas from random matrix theory and quantum information theory determine significant numbers like prediction error variance.

Even if theoretically and mathematically sound, the study simplifies concepts like the Marchenko Pastur rule, Hawking radiation, and the Page curve into a single analytical framework. Unfeasible assumptions include monitoring or manipulating quantum information at infinitely fine scales, an accurate quantum gravity theory, and complete understanding of quantum black hole microstates. Even though their analogies are mathematically valid, the authors do not claim black holes perform machine learning. Instead, they claim that both systems have similar information-theoretic constraints.

Future Quantum and AI Research Prospects This interdisciplinary approach may allow academics to re-examine quantum gravity problems using AI. Variance and bias may offer new insights into information behaviour under extreme physical restrictions, like entropy and temperature did for black holes.

However, black hole learning dynamics may provide novel models for how quantum machine learning systems generalise in the face of data overcapacity or scarcity. This study adds to studies on enhancing learning algorithms and understanding the universe's most intriguing riddles. A unified mathematical language links physics and machine learning.

Preprint authors: Spinor Media's Zae Young Kim and Jungwon University's Jae-Weon Lee. The arXiv paper lacks peer review, a necessary scientific step.

[sarallokesh37]

IBDP Physics Guide 2025: Your Complete Roadmap to Success

Why Choose IBDP Physics?

Physics is the foundation of all modern science and technology. Whether you're fascinated by space exploration, engineering innovations, climate change, or quantum computing, physics offers insights into how the world works.

The IBDP Physics course fosters critical thinking, problem-solving, and analytical reasoning. These skills are valuable not only for scientific careers but for any profession that demands logical and data-driven thinking.

IBDP Physics Guide 2025 aims to equip you with practical strategies, explain the course structure, and help you excel in this rewarding subject.

Course Structure: What You Will Study

In the IBDP, students select six subjects from different groups, with three studied at Higher Level (HL) and three at Standard Level (SL). Physics belongs to Group 4 – Sciences.

Whether you choose HL or SL, IBDP Physics offers a comprehensive exploration of core and advanced topics. HL students study additional content and at greater depth.

Core Topics (HL and SL)

Measurements and Uncertainties

Mechanics

Thermal Physics

Oscillations and Waves

Circular Motion and Gravitation

Electricity and Magnetism

Atomic, Nuclear, and Particle Physics

Energy Production

Optional Topics (Chosen by the school)

Relativity

Engineering Physics

Imaging

Astrophysics

The Philosophy of Physics in IBDP

Physics is not simply about learning formulas. The IBDP Physics Guide 2025 encourages you to develop:

An appreciation of the scientific method

An understanding of how science impacts society

Ethical considerations in technological development

An ability to communicate complex ideas clearly

Assessment Model

Assessment in IBDP Physics is designed to test a wide range of skills:

External Assessments

Paper 1: Multiple-choice questions testing your breadth of knowledge.

Paper 2: Structured short-answer and extended-response questions assessing understanding and problem-solving ability.

Paper 3: Questions based on experimental work and optional topics.

Internal Assessment (IA)

A crucial part of the course, the Individual Investigation is a student-designed experiment, contributing 20% of the final grade. You will:

Select a topic of interest.

Formulate a research question.

Design and carry out an experiment.

Analyze data and evaluate your findings.

Assessment Goals

By the end of the course, you should demonstrate:

Knowledge and comprehension of concepts, theories, and formulas.

Application and analysis of physical principles.

Evaluation of scientific arguments and real-world applications.

Experimental skills and the ability to conduct independent research.

Why Physics Matters

Physics is integral to every scientific discipline. Modern society depends on technological innovations rooted in physics:

Energy and Sustainability: From solar panels to nuclear reactors.

Communication: The internet, GPS, and mobile networks rely on satellite physics and quantum mechanics.

Medicine: MRI scans, radiation therapy, and medical imaging all use physics.

Space Exploration: Rocket science, satellite technology, and cosmology are direct applications of physics.

IBDP Physics Guide 2025 shows how studying this subject connects you to real-world challenges and innovations

Historical Perspective

Understanding physics also involves appreciating its history. From the ancient Greeks’ celestial studies to Newton’s Laws of Motion and Gravitation, each era has expanded our understanding of the universe.

The 20th century saw two revolutionary developments:

Einstein’s Theory of Relativity, reshaping our view of space, time, and gravity.

Quantum Mechanics, unlocking the mysteries of the subatomic world.

Today’s digital age — with semiconductors, lasers, and the Internet — is built upon these discoveries. By studying IBDP Physics, you join a lineage of inquiry that continues to shape the future.

Tips for Success: How to Excel in IBDP Physics

Build Clear, Organized Notes Maintain comprehensive IBDP Physics notes for each topic. Include definitions, key formulas, diagrams, and real-life examples.

Master Diagrams Diagrams are a powerful tool for visualizing concepts like waves, fields, and circuits. Practice drawing them accurately.

Practice Past Papers Regularly solving past exam papers familiarizes you with question formats and improves time management.

Understand, Don’t Memorize Grasp the underlying principles rather than memorizing equations. Physics rewards conceptual understanding.

Engage in Experiments The IA offers a chance to explore a topic you find fascinating. Choose something meaningful, plan carefully, and reflect critically.

Link Theory to the Real World Stay updated on current scientific developments — from renewable energy to space exploration — and connect these to your coursework.

Seek Support When Needed If you face challenges, consult your teachers or consider external resources like Tychr, where expert IB tutors provide personalized guidance.

Why IBDP Physics Is Worth It

IBDP Physics is challenging — but the rewards are immense:

Intellectual Growth: You will learn how to think critically and solve complex problems.

Academic Preparation: Physics is excellent preparation for fields like engineering, computer science, medicine, architecture, and even finance.

Global Opportunities: Universities worldwide value the rigour of IBDP Physics and the analytical mindset it fosters.

Conclusion: Your IBDP Physics Journey Starts Now

This IBDP Physics Guide 2025 offers a roadmap to success. Whether you're passionate about understanding the universe or preparing for a STEM career, Physics will empower you with skills that last a lifetime.

Embrace the challenge, stay curious, and keep connecting what you learn to the world around you. From ancient astronomers to today’s quantum scientists, you are continuing a tradition of exploration and discovery.

And remember — with expert support from resources like Tychr, you’re never alone on this exciting journey.

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