Unruh Effect (Quantum Field Theory 2k)

If you accelerate enough, you will feel the burn

[@shreeshholla5127]

Really well done lecture. Taken a complex topic and made it so simply intuitive.

[@GeoffryGifari]

first off, a fan of how you present this as a story, how first accelerated motion in special relativity can give rise to a horizon

[@keith.anthony.infinity.h]

Hello I am a physics major. I was wondering are you as well and are you pursuing research? If so you are doing a wonderful job understanding the content. We need more African, African American, and POC youth in STEM.

[@FermionPhysics]

Yep, I am a physics major. I’m currently doing research, but with nuclear engineering. I’ll be doing some theory research in QFT sometime soon.

[@keith.anthony.infinity.h]

@@FermionPhysics That is amazing my field of research is in Quantum Gravity. I am based in Colorado state but would you like to maybe stay in contact to talk about each other’s ideas? There maybe some stuff missing in the ideas I am working that you could possibly notice to correct from a particle physicist’s perspective.

[@Naomi_Boyd]

Each time you accelerate, the amount of time you gain is reduced, and the distance to the light is always reducing. Eventually the time you gain will be less than a Planck time, and the distance will be less than a Planck distance, and the light will catch up. This is just Zeno's paradox rewritten for the modern day.

[@vanikaghajanyan7760]

Expansion is a special kind of motion, and it seems that the Universe is a non-inertial frame of reference that performs variably accelerated motion (according to general estimates, this acceleration is: a=πcH).* Real gravitational fields are variable in space and time, and, developing GR**, we can now talk about the fact of the possibility of generating gravitational field in a non-inertial frame of reference (a=g).. That is, finally achieve global (instead of local in GR) compliance with the equivalence principle. Then the energy density of the relic radiation, that is, the evolving primary gravitational-inertial field (= space-time): J= g^2/8πG ~1500 quanta /cm ^3, which is in order of magnitude consistent with the observational-measured data (about 500 quanta/cm ^3). By the way, it turns out that the universe is 1.6 trillion years old! P.S. You can also use the Unruh formula, but with the addition of the coefficient q, which determines the number of phase transitions of the evolving system: q=√n', where n'=L/8πr(pl), L=c/H. Thus, T*(relic)=[q]ħa/2πkc (=0,4K), which is in order of magnitude consistent with the observational-measured data: T(relic)/T*(relic)=2,7/0,4=6,7. {However, it seems that the presence of a factor 1/2π in the Unruh formula is not entirely physical.} --------------------- *) - w(relic)^2=πw(pl)H, a=r(pl)w(relic)^2 =g=πcH, intra-metagalactic gravitational potential: |ф0|=πGmpl/λrelic , m(pl)w(pl)=8πM(Universe)H; { w(relic)^2=πw(pl)H. **) - See "GR was QG".

[@vanikaghajanyan7760]

GR was QG: docs.google.com/document/d/1FyD9vlFkQmVuVHWXNJSuuk6T86aJqqFG/edit?usp=drivesdk&ouid=110286572639581187540&rtpof=true&sd=true

[@GeoffryGifari]

A couple of things i like to think about this: 1. Does plugging rindler metric in Klein-gordon equation mean an outside, accelerated observer perceiving the behavior of klein-gordon field, or does it mean an excitation of the Klein-gordon field moving with a constant acceleration? 2. The rindler horizon is created through constant acceleration, which means we can change the “shape of the horizon” and whether or not it exists by lowering/raising the acceleration (assuming we can do that). If we slow down and speed up in such a way that the horizon “turns on and off”, would interesting things be happening with regards to QFT?

[@FermionPhysics]

1. This is a really interesting question…I’ve never thought of that before. I think it should be the quantum field as perceived from an accelerated observer, where the accelerated observer does not have to be a “quantum mechanical” object/excitation. Kind of like in classical mechanics where the different frames of reference don’t have to have their internal properties specified (size, shape, mass, charge, etc)…maybe 2. I think that if the horizon flickers on and off, all that would happen would be that it would look like particles pop in and out of existence from accelerating frame’s perspective. I don’t think any extra effects would happen, but I’d have to do a separate calculation to be sure. We would have to look at the frame of an observer that oscillates between 0 proper acceleration and some positive constant acceleration w with a form of a(t) = sin(t) + w where w>0. Then the temperature should also be a function of t. I bet it would probably just be T=a(t)/2pi instead of just a/2pi. That would be a nice calculation for a research paper.

[@GeoffryGifari]

@@FermionPhysics 1. I thought of this because when doing field theory calculations (with minkowski metric), we refer to the field excitation itself as "the thing", but calculations with accelerated observer requires relative motion between accelerated and inertial frame, so i still don't understand exactly which one is "the thing", especially when the metric is plugged directly to the equation of the field instead of an inertialy moving source term (like an observing "charge") 2. Think about it, thermodynamically change in temperature corresponds to heat and work, so maybe the extra oscillating acceleration term corresponds to doing "work" to QFT vacuum (?) fascinating stuff

[@FermionPhysics]

Skip to 33:00 if you know relativity

[@imaginingPhysics]

Maybe interested to see rindler horizon in first person?: kzbin.info/www/bejne/haXTXph4fbF9sLM

[@grzegorzmajcher9237]

Aaaaaaaaaaaaaaaaaaaah! Please, do not produce any more videos about physics!!!