Bose Einstein condensates and GR?

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Discussion Overview

The discussion explores the relationship between Bose-Einstein condensates (BECs), general relativity (GR), and quantum field theory (QFT). Participants consider how macroscopic entangled systems like BECs interact temporally with themselves and larger systems, and what experimental observations could elucidate the connection between GR and QFT.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions how BECs relate temporally to themselves and larger systems, given their macroscopic nature and the influence of GR.
  • Another participant asserts that every particle is affected by gravity and obeys quantum mechanics, suggesting that combining weak gravitational fields with quantum mechanics is feasible.
  • A participant shares a personal insight inspired by Leonard Susskind's work, pondering how BECs might interact with other astronomical systems and the implications for spacetime curvature.
  • Concerns are raised about the possibility of defining an arrow of time for quantum systems using entropy, with one participant arguing that all systems are quantum mechanical and that entropy must increase over time in quantum mechanics.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between entropy and the arrow of time in quantum systems. There is no consensus on how BECs interact with larger systems or the implications for GR and QFT.

Contextual Notes

Participants acknowledge limitations in their understanding of advanced physics concepts, with one noting their background in electromagnetism and inexperience with upper-level mathematics.

Digitalism
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If time is constantly moving the direction of increasing entropy and quantum systems are time symetric then how do macropscopic entanlged systems such as bose-einstein condensates relate temporally to themselves and larger systems of which they might be subsets? Because BECs are large enough to be be affected by GR and yet obey the laws of quantum mechanics what kinds of observations/experiments could be utilized to take advantage of their features in order to better understand the relationship between GR and QFT?
 
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What do you mean with "relate temporally to themselve and larger systems [...]"?

Because BECs are large enough to be be affected by GR
Every particle is affected by gravity, and every particle obeys the laws of quantum mechanics.

It is not an issue to combine weak gravitational fields with quantum mechanics. Experimentally, this can be done with neutrons (1) and molecules (I think http://www.nature.com/nnano/journal/v7/n5/full/nnano.2012.34.html?WT.ec_id=NNANO-201205 is the right reference).
 
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Sorry, this was a eureka moment I had while listening to Leonard Susskind's Black Hole Wars. I will have to re-download the audiobook so I can find the exact quote so I can say exactly how it influenced my thoughts on the question exactly. Basically, he made a comment about quantum systems being time symmetric and not being able to draw an arrow of time due to entropy for those systems, so how would a large bose-einstein condensate interact in terms of time with other massive astronomical systems? The bosons would curve spacetime in some way which would make them have an impact on other astronomic phenomena and vice versa so what would the spacetime of the bec look like and how would that differ from say a bunch of entangled photons interacting on the subatomic level? Also, would it be possible to sustain the the condensate and scale it up? For example say you had a collection of bosons with 3 solar masses encased in a sort of sheath in vacuum what would the condensate look like as it collapsed so a singularity? I am trying to come up with "thought experiments" that could be avenues for GR and QFT unification

I have only taken up to electromagnetism though, so I am still new to upper level physics esp the mathematics
 
Digitalism said:
he made a comment about quantum systems being time symmetric and not being able to draw an arrow of time due to entropy for those systems

I don't know what source material you are referring to here, but I think there is no problem in using entropy to define an arrow of time for "quantum systems." *All* systems are quantum mechanical, so the second law would be in serious trouble if entropy did not increase with time in quantum mechanics.
 

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