/r/Physics

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For physicists and physics students. See the rules before posting, and the subreddit wiki for common questions. Basic homework questions are not allowed.

/r/Physics is for physicists, scientists, graduate and undergraduate physics students, and those with a passion for physics. Posts should be pertinent and generate discussion.

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Weekly schedule

All threads are posted at 9am EDT (1pm UTC).

Day Post
Mon What are you working on?
Tue Physics Questions
Thu Careers/Education Questions
Fri Resource Recommendations

/r/Physics

2,944,817 Subscribers

0

The Theory of Quantum Holographic Feedback - A new mathematically grounded theory describing observations, and predicting Dark Matter and Dark Energy effects, brought together by AI 4o

Core Idea

Dark matter and dark energy arise from a feedback mechanism between quantum processes and the large-scale structure of spacetime, facilitated by a holographic encoding of the universe’s quantum information on its boundaries. This feedback creates emergent gravitational effects and drives cosmic expansion without requiring new particles or fields.

Components of the Theory

Holographic Principle

  • The universe operates as a hologram: all information about its quantum state is encoded on a lower-dimensional surface (e.g., the cosmic horizon).
  • Gravitational effects arise from the projection of this information into the higher-dimensional "bulk" spacetime.
  • Dark matter and dark energy emerge as byproducts of the tension between the holographic surface and the bulk dynamics.

Quantum Entanglement on Cosmological Scales

  • On small scales, quantum entanglement influences the behavior of particles. On large scales, entangled quantum states across the holographic surface influence spacetime geometry.
  • This entanglement generates additional gravitational effects that mimic the influence of dark matter.
  • These effects are strongest in regions with high curvature (like galaxies) and weaker in voids, matching dark matter distribution.

Feedback Mechanism and Cosmic Expansion

  • The universe’s accelerated expansion is driven by feedback between the encoded quantum states on the horizon and the bulk spacetime.
  • This feedback creates an effective repulsive force, akin to dark energy, as the holographic surface evolves to maintain equilibrium with the expanding bulk.
  • This dynamic replaces the need for a cosmological constant or quintessence field, instead linking cosmic acceleration to the quantum-state density on the cosmic boundary.

Emergent Gravity and Dark Matter

  • Instead of being a new form of matter, dark matter represents a collective quantum effect, akin to a residual gravitational "memory" from the holographic encoding.
  • This emergent gravity strengthens spacetime’s curvature in regions of high mass without requiring additional mass itself, explaining phenomena like galactic rotation curves.

Predictions and Tests

Galactic Dynamics

  • The distribution of "dark matter effects" would align precisely with predictions from entanglement density across the holographic surface, which can be tested through detailed gravitational lensing studies.

Cosmic Microwave Background (CMB) Anomalies

  • The quantum-holographic feedback should leave subtle imprints in the CMB, such as deviations in temperature anisotropies correlated with cosmic horizon geometry.

Expansion Rate Variability

  • The holographic mechanism predicts slight variations in cosmic expansion over time, testable with next-generation observations of Type Ia supernovae and gravitational waves.

Laboratory Simulations

  • Quantum simulations of holographic systems might reveal emergent gravitational phenomena analogous to dark matter effects, providing experimental validation.

Benefits of the Theory

  • Unification of Concepts: Merges quantum mechanics, relativity, and holography into a single framework, reducing the need for speculative new particles or exotic energy fields.
  • Consistency with Observations: Matches observed phenomena like galaxy rotation curves, gravitational lensing, and cosmic acceleration.
  • Testability: Offers clear, falsifiable predictions for astrophysical and laboratory experiments.
  • Philosophical Appeal: Explains dark matter and dark energy as emergent properties of fundamental principles rather than mysterious new entities.

This theory reimagines dark matter and dark energy as the natural consequences of a quantum feedback system intrinsic to the universe's holographic nature, opening new avenues for exploration in both cosmology and quantum physics.

----------------------------

Formalizing the Quantum Holographic Feedback theory mathematically is a challenging task, as it involves synthesizing elements from quantum mechanics, general relativity, and the holographic principle. Below is an attempt to outline a preliminary mathematical framework that could underpin the idea:

1. Holographic Principle and Boundary Dynamics

https://imgur.com/w4dEsXU

2. Quantum Feedback Mechanism

https://imgur.com/7sBJylB

3. Emergent Dark Matter Effects

https://imgur.com/WnpBX9d

4. Emergent Dark Energy Effects

https://imgur.com/ymc5NOv

5. Unified Framework

https://imgur.com/G5HjHbu

Predictions and Parameters

Galactic Rotation Curves:

  • Predicts deviations in gravitational acceleration without requiring dark matter particles.

Cosmic Expansion:

  • Predicts subtle changes in the Hubble constant over time.

CMB Anomalies:

  • Predicts boundary entanglement affects early-universe perturbations, leaving signatures in the CMB power spectrum.

https://imgur.com/hJh84cI

Next Steps

Numerical Simulations:

  • Develop models to solve the coupled boundary-bulk equations for specific cosmological scenarios.

Comparisons to Observations:

  • Test the theory against galaxy rotation curves, lensing data, and supernova observations.

Quantum Analog Systems:

  • Simulate boundary entanglement and its feedback in condensed matter systems or quantum computers.
1 Comment
2024/12/09
08:56 UTC

6

Can a LEGO Reactor Model Make Nuclear Physics Easier to Understand?

Hi fellow physicists and science lovers!

Nuclear physics sometimes feel abstract and complex, but what if we could make it more accessible, and even fun, using LEGO?

Let me introduce the LEGO model of CROCUS, a real nuclear reactor used for teaching and research at EPFL, Switzerland. This unique model is designed to make nuclear science and reactor design more tangible and relatable.

🔍 How does it connect to physics?

As a university physics teacher, I've explored creative ways to teach nuclear concepts. This LEGO model has proven effective for:

  • 🔬 Approaching concepts like neutron moderation, nuclear fission, and core physics
  • 🎓 Bridging abstract ideas with hands-on understanding
  • 💡 Inspiring both students and newcomers during outreach events.

🙋 What do you think?

  • Could tools like this enhance teaching or learning experiences in physics?
  • What other complex physics topics could benefit from such hands-on models?

(PS: If you're curious, the project is featured on LEGO Ideas to make it an official set, and and you can read more about it in this detailed article.)

The Lego model of the CROCUS reactor, whose core and internals are visible thanks to the openable vessel.

2 Comments
2024/12/09
08:12 UTC

70

What to tell this redditor?

I told him force is not same as speedm pulling something faster makes no sense.

And even if we consider GTR. The change of gravitational field will b e same as speed of light. How to give him a well articulate answer. Or am I being wrong. Also English isn't my strong suit so it is sometimes hard for me to explain something to others

93 Comments
2024/12/09
06:19 UTC

30

Why is red light darker than any other colour (expect of white)

So recently we put some lights for Christmas in our home. Right before i was going to school until the red light showed up, amd I wasn't seeing as much as i could see with blue and green. So i pulled out my phone, recorded it, amd came here to hopefully fin an answer to the question above.

Sorry for my english, It's not my first language

18 Comments
2024/12/09
05:27 UTC

10

Thoughts on the field of quantum control?

Hi, I'm currently in my 3rd year physics undergrad and I just finished our control systems class. I thought control theory is really fun. So now I'm thinking what if for my thesis (or graduate thesis) I study the applications of control theory on quantum systems?

What do you think of this? What is the research like in this field?

Any insights is welcome! Thank you.

PS. no one in my university does research in this field so i dont think I will do it for my undergrad

5 Comments
2024/12/09
05:12 UTC

97

Introducing the Metric Tensor: a natural consequence arising from dual vectors and the inner product

14 Comments
2024/12/08
02:14 UTC

55

Physicists vs Mathematician doing Maths

I am a 1st year Theoretical Physics but I am slowly realising I am bad at Physics and okay at Maths. Then, I wondered whether Mathematical Physics is more ideal for me.

Anyway, my question is: how exactly does it differ between a physicists and a mathematician doing maths?

Obviously we have different research topics but other than that, let's assume a physicist and a mathematician is approaching the same problem. What would the difference be? The obvious one I have in mind is how rigorous we are (my maths module lecturer from the physics department literally doesn't care about the modulus for , say, integral 1/x dx)

54 Comments
2024/12/07
22:10 UTC

55

How to optimize a Cloud Chamber, based on my experience

Hey guys! You all probably know what a cloud chamber is (if not, it's basically the simplest particle detector you can build at home, great for visualization and teaching), but If you ever tried to build one, you probably noticed just how different the instructions on Youtube and the internet might be. I recently worked on a project for school where I tried to improve the cloud chamber as much as possible, and wanted to share what worked for me and didn't. Note: though I tried to justify my results scientifically in the study, it still might be wrong and my suggestions might go against theory, in which case please correct me. Also, some of these tips might be already available online, and I don't claim to have invented them. Anyhow, here's a list of suggestions:

- For starters, check out the two following videos: 1) https://youtu.be/xky3f1aSkB8?si=VGAR5G1y6HTRyX3f and 2) https://youtu.be/eh3bxXHqF2U?si=zh_Ju3Gc150XQVr8 . I found these resources extremely helpful as the initial guide. The CERN one uses a metal sheet with grooves, however these are hard to find or do by yourself. So, follow ElectroBOOM's suggestion to make a silicon groove, it generally helps with the sealing and fixes the chamber container in place.

- Use glass or plastic for the chamber container. Some people suggested using plexiglass, which I ended up using, and do not recommend you do. Since we cool the chamber, the low temperature ended up cracking the container for me, leading to leaks at the bottom. Generally it's easier to get a ready container (from cooking sets or smth) rather than building you own, cause mine was imperfect and had gaps, which I had to glue together for some time.

- For the alcohol absorbent, use felt, not sponge. Felt can collect more alcohol and generally spreads it better than sponge. Also, the felt should cover the entire area of the top layer of the container, as it evenly spreads the alcohol. The felt layer should be quite thick (around 3-4 cm), as it allows to pour a sufficient amount of alcohol.

- Concerning the alcohol itself. It's best to use isopropanol, but for personal use different alcohols (methanol, ethanol, etc) are quite sufficient. I personally used ethanol because isoprop isn't sold in my region. Try to hit >90% purity - generally the higher you go the better the tracks. The cloud chamber has a specific limit of alcohol quantity where it actually operates, i.e if you poor too little or too much, it won't display tracks. If you have the time, try to play around with the volume of the vapor to see where this region lies for you - you will also see a change in the quality of the tracks, as some volumes produce a high number of tracks, others display them for longer. But if you're low on alcohol or just want to see the chamber work, the rule of the thumb is to cover the entire area of the felt and pour out the excess.

Also, the waiting time until the chamber actually starts displaying particles varies based on the amount of alcohol you add. So, for smaller volumes it took me about 10 minutes to start up, and 20 for higher volumes.

- For the metal sheet (which you place on top of your cold layer, where you actually see the tracks), try to find a black one. Aluminum, etc won't display as good and reflects light.

- The temperature gradient between the top and bottom layer plays a big role. It's best to get the bottom layer as cold as you can by using dry ice. Flaked ice worked best for me, as it covered the whole metal sheet area. Pellets work good as well. But if you plan to make more of a "perpetual" cloud chamber, go with Peltier coolers submerged in frozen salted water. This, however, will deteriorate the quality of your tracks, so judge based on your use. You can place hot water on your top layer, which will also improve your quality. I tried making a chain of resistors to heat the felt directly, but failed to do so. Maybe you'll be able to make it, but please be careful and look into it further because I'm not sure if it might actually ignite the alcohol :)

- If you want to produce more tracks rather than relying on cosmic rays, order smoke detectors with Americium-241 (I got them off of Aliexpress. Bought 10, only 3 produced decent results). Some recommend thorinated welding rods, but I went with the detectors. Remember radiation safety. Also, place the detector inside rather than trying to produce tracks from outside the container, plastic blocks off the particles.

___________________

Hope this helps! Have fun, I loved my experience with the chamber.

Edit: If you're concerned about the price of the chamber, the whole thing cost me around 30-40 usd, 20 of which went to the dry ice order. So shouldn't be too much

9 Comments
2024/12/07
13:29 UTC

122

Barry Barish's Take on Imposter Syndrome

We were lucky enough to have Barry Barish speak at an informal round table event at Stony Brook University, and someone asked how to deal with imposter syndrome, feeling like every other student/physicist could do everything so much better than you, like you could never do anything significant next to them.

Barish explained that he felt particularly inadequate when he went to sign off on his Nobel Prize.

"Getting the Nobel Prize is this whole week long process, and I'd been doing well so far. The last day, they took us to get the money, take pictures, do all the important things. They came up to me with this nondescript, small book, and opened up this page that was blank except for '2017' at the top. 'Sign here,' they said. I signed my name, and flipped through the book. I saw Einstein, Feynman, all these fantastic physicists who changed the world... how could I be in this book? But I had already written in pen, so I couldn't erase my name."

I hope this brings you guys as much comfort as it did me, that even the most accomplished physicists feel this way at one point or another.

9 Comments
2024/12/07
03:11 UTC

13

Textbooks & Resources - Weekly Discussion Thread - December 06, 2024

This is a thread dedicated to collating and collecting all of the great recommendations for textbooks, online lecture series, documentaries and other resources that are frequently made/requested on /r/Physics.

If you're in need of something to supplement your understanding, please feel welcome to ask in the comments.

Similarly, if you know of some amazing resource you would like to share, you're welcome to post it in the comments.

1 Comment
2024/12/06
14:00 UTC

47

How can scientists simulate an entire universe such as the uchuu simulation, but can't solve the 3 body problem. For that matter, how can we predict so accurately the movement of the planets?

72 Comments
2024/12/06
12:48 UTC

48

Visualizing the Chaos in Non - Linear Springs SHM | Why Chaos?

6 Comments
2024/12/06
03:29 UTC

10

Careers/Education Questions - Weekly Discussion Thread - December 05, 2024

This is a dedicated thread for you to seek and provide advice concerning education and careers in physics.

If you need to make an important decision regarding your future, or want to know what your options are, please feel welcome to post a comment below.

A few years ago we held a graduate student panel, where many recently accepted grad students answered questions about the application process. That thread is here, and has a lot of great information in it.

Helpful subreddits: /r/PhysicsStudents, /r/GradSchool, /r/AskAcademia, /r/Jobs, /r/CareerGuidance

14 Comments
2024/12/05
14:00 UTC

24

Physics-themed calendar?

Hi all, not sure this post is allowed, in case not, feel free to remove it. I was thinking of buying a 2025 paper calendar as a decoration and I was looking for a science-themed one (preferably physics) do you know of a nice one? From a place that posts in Europe possibly.

4 Comments
2024/12/05
12:45 UTC

68

Even if a quantum computer that surpasses a classical computer is never successfully built, what are some useful research that has/will bear fruit along the way?

This is similar to a previous question on fusion energy, which I'm really curious about the answers for quantum computing too.

I believe there's always some nuance involved in these fields dedicated to building these technologies that're hailed as breakthroughs, it's not all or nothing.

With all this research going into it, there's bound to be at least some useful research done that could benefit other fields right? Be it on the experimental or theoretical side?

118 Comments
2024/12/03
15:15 UTC

13

Physics Questions - Weekly Discussion Thread - December 03, 2024

This thread is a dedicated thread for you to ask and answer questions about concepts in physics.

Homework problems or specific calculations may be removed by the moderators. We ask that you post these in /r/AskPhysics or /r/HomeworkHelp instead.

If you find your question isn't answered here, or cannot wait for the next thread, please also try /r/AskScience and /r/AskPhysics.

30 Comments
2024/12/03
14:00 UTC

18

Accelerated Structure Formation: The Early Emergence of Massive Galaxies and Clusters of Galaxies

Paper is open access - link to paper

Great Blog by Prof. Stacy McGaugh - The most recent post is about his and collaborators recent paper about JWST results and structure formation. Link to blog

Highly recommend the blog, whether you are interested in Galaxy dynamics or not, simply because it is great and McGaugh has all the hallmarks of a good guy and great communicator. As ever, judge the physics for yourself.

4 Comments
2024/12/01
20:54 UTC

61

What made you interested in physics?

My reason for getting into and being interested in physics is quite odd now i look back on it, but i got interested in physics when a truck went past me going quite fast which generated a gust of air/wind

Then i started to think about how and why that happens, so i went home that day and started doing some research, and from that point on, i was hooked.

74 Comments
2024/12/01
20:36 UTC

42

What is the Main Motivation for Weak Scale Supersymmetry (SUSY) After the Negative Results from the LHC, XENONnT, Searches for Proton Decay, EDM, etc.?

SUSY is an attractive (and natural) property to have for our world especially if we want to build a theory of quantum gravity (vis-a-vis, superstring theory, supergravity etc.). And I understand the basic motivation behind it too, why would nature, after all, not utilize spin 3/2 when she already utilizes the others (0, 1/2, 1, 2). However, for quantum gravity we only need SUSY at the Planck scale NOT at the Weak scale. So massively broken SUSY is not an issue for quantum gravity.

From my understanding the original motivation some 40 years ago for expecting Weak scale (slightly broken) SUSY was as follows:

  1. The so-called WIMP miracle, a candidate for dark matter,
  2. Exact unification of the coupling constants at GUT scale,
  3. Fixing the Heirarchy problem and the Higgs mass,
  4. 'Improving' the discrepancy in the cosmological constant problem.

(If I have understood these incorrectly or if you want to add more reasons, feel free to correct me!)

Now, from what I understand the non-detection of SUSY or WIMPs at the LHC and dark matter experiments (with XENONnT, LZ, etc., now hitting the neutrino floor), along with the growing limits on proton decay and EDM for SUSY models, we are reaching the limits of what SUSY was intended to fix in the first place!

So, my question is, am I missing something from this picture? Is there still any good motivation for Weak scale SUSY?

14 Comments
2024/12/01
10:47 UTC

131

I graduated 8 years ago with a B.Sc and M.Sc in Physics and Chemistry Honours.

Graduated 8 years ago with a B.Sc and M.Sc in Physics and Chemistry Honours. I still reminisce about the late nights in labs, study groups, and the joy of learning with friends. I wanted to do a PhD but couldn’t stand the 7-year slog of academic bureaucracy. Recently, I’ve been diving back into my undergrad notes to relearn and keep my mind sharp. Feels good to reconnect with what I love.

28 Comments
2024/12/01
02:08 UTC

9

An academic discussion on new approaches in Complex Riemannian Manifolds and Kaluza Klein Theory.

1 Comment
2024/11/30
20:02 UTC

14

Who was R Rinkel?

I'm currently writing a report on the Ruchardt and Rinkel experiments I did in my uni labs, and while trying to look into the background of both, I found nothing about Rinkel, not even a first name beyond "R". I don't need anything more than the experiment for my report, but out of personal curiosity, does anyone know anything more about Rinkel?

8 Comments
2024/11/30
15:20 UTC

39

What is the physical significance of action?

I've started quantum mechanics. I know momentum and distance pair or energy time pair is significant in qm. But why is momentum*distance defines action? What does this quantity actually represent? And why is reduced planck const the minimum value of action?

55 Comments
2024/11/30
09:56 UTC

11

Textbooks & Resources - Weekly Discussion Thread - November 29, 2024

This is a thread dedicated to collating and collecting all of the great recommendations for textbooks, online lecture series, documentaries and other resources that are frequently made/requested on /r/Physics.

If you're in need of something to supplement your understanding, please feel welcome to ask in the comments.

Similarly, if you know of some amazing resource you would like to share, you're welcome to post it in the comments.

16 Comments
2024/11/29
14:00 UTC

0

AI/CS discussion is already very hot on alphaxiv, but physics is still cold. Isn't physics the origin of arXiv?

8 Comments
2024/11/29
10:16 UTC

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