Questions tagged [poincare-recurrence]
45 questions
27
votes
3 answers
Is Poincare recurrence relevant to our universe?
If the theory of everything indicates a singularity-free and finite universe, will Poincare recurrence be relevant to the universe? If so, is there any interesting physical consequence, e.g. in superstring or quantum gravity?
Jiajun
- 373
17
votes
3 answers
Is decoherence even possible in anti de Sitter space?
Is decoherence even possible in anti de Sitter space? The spatial conformal boundary acts as a repulsive wall, thus turning anti de Sitter space into an eternally closed quantum system. Superpositions remain superpositions and can never decohere. A…
theorist
- 171
16
votes
7 answers
Is the second law of thermodynamics even a law?
I am a high school student trying to wrap my head around the second law of thermodynamics for the past few days to no avail. Having only a cursory knowledge of calculus, and chemistry and physics in general doesn't help either.
The second law of…
Manit Agarwal
- 517
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15
votes
1 answer
Poincaré maps and interpretation
What are Poincaré maps and how to understand them?
Wikipedia says:
In mathematics, particularly in dynamical systems, a first recurrence
map or Poincaré map, named after Henri Poincaré, is the intersection
of a periodic orbit in the state…
user929304
- 4,910
10
votes
4 answers
Why aren't we Boltzmann brains in an infinite universe?
Either space is finite or it is infinite.
a) - If space is infinite in extent, either it is thermal over an infinite volume, or it is in the vacuum state for most of it. If it is thermal, infinity is a large place, and random statistical…
Mad scientist
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7
votes
0 answers
Poincare recurrence and the multiverse
In this paper Susskind claims that a stable de Sitter universe is problematic (among other things) due to the existence of Poincare recurrence, which happen because of finite entropy. I disagree that this is a problem for reasons similar to those…
Bubble
- 2,070
6
votes
1 answer
Example of Poincare recurrence theorem?
Is it possible to explain Milankovitch cycles (or some other arbitrary planetary configuration that recurs to some approximation) in terms of the Poincare recurrence theorem?
More generally, is there a good physical example of the Poincare…
daniel
- 664
5
votes
3 answers
Are the claims about repeating states and space in Netflix's "A Trip to Infinity"'s based on real research?
I just watched Netflix's documentary on infinity "A trip to infinity". They have an example where you put an apple in a perfectly sealed box. They make a claim that seems odd to me.
The apple will decay etc etc but because there are a finite number…
Fergal Daly
- 61
5
votes
3 answers
Why did Poincaré's recurrence theorem represent Harm to Kinetic Theory of Gases?
Poincaré's recurrence theorem remained as far as I know, unproven until 1919 when Caratheodóry proved it. Why then did it represent an issue to Boltzmann? Boltzmann died in 1906, did he not know about this? I believe he did, because his ergodic…
5
votes
2 answers
Calculating Poincare recurrence times
I am interested in calculating the Poincare recurrence time of a physical system (i.e. a system with with continuous time evolution). I have seen physics papers giving estimations of the recurrence times but never any formula how they estimated it.…
UtilityMaximiser
- 817
5
votes
3 answers
Poincaré Recurrence and Immortality
If, as Luboš Motl says, Poincaré recurrence is relevant for our universe, does this mean (1) that, after I die, I'll one day live through my life again after the same physical pattern that is currently me reconfigures and (2) that I'm thus immortal…
Horton Hears
- 151
5
votes
2 answers
Is entropy related to Poincare recurrence time?
One of the ideas involved in the concept of entropy is that nature tends from order to disorder in isolated systems. But we even know that Poincare recurrence time also is a particular time after which a system of particles get back to their…
4
votes
1 answer
Liouville's Theorem & Flows in Phase Space for Particle in a Box
A Hamiltonian system of $100$ interacting oxygen atoms, each of mass $16$
$m_p$, is confined within a cubical box of sides $1 m$. The average initial
speed of each particle is $300 ms^{-1}$. Estimate the timescale for the
system to return close to…
Poo2uhaha
- 555
4
votes
2 answers
What to think of the convergence of the logarithmic integral and its repercussions in QM?
Suppose we prepare a certain quantum system with Hilbert space ${\cal H}$, a self-adjoint Hamiltonian operator $H:{\cal H} \to {\cal H}$ whose spectrum is bounded below by $E_0\in \mathbb{R}$ (i.e. the energy is bounded below), and with initial…
Hecatonchires
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3
votes
1 answer
What is the probability of ice in boiling water?
Ice crystals are spatially ordered, and in every randomness there is a low possibility of temporarily order. If given enough boiling water, and sufficient time, could local clusters water molecules happen to be in a crystalized state?
This may seem…
TiansHUo
- 167