sokendai satoshi iso okazawa sen zhang sokendai)lt.riken.jp/symposium/symmetry/download/iso.pdf ·...
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Non‐Equilibrium Fluctuations of Horizons
Theory Center , KEK & Sokendai
Satoshi Iso
based on a collaboration (gr‐qc/1008.1184) with Susumu Okazawa & Sen Zhang (KEK, Sokendai)
岡澤晋 張森
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( 23 July, 2010 @ Riken, Wako )(26 July, 2010 @ Journal club, KEK)
Planck units
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Plan of the talk
Chap. 1 Physics of horizonsThermodynamic Laws (Classical vs. Quantum) of Black holes
Chap. 2 Non‐equilibrium thermodynamicsCrooks fluctuation theorem & Jarzynski equality
Chap. 3 Fluctuation theorem for Black Hole horizons・Transition amplitude for changing area of horizon・Proof of the Generalized second law
and its microscopic violation
Chap. 4 Conclusions and Discussions・speculations
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Chapter 1Physics of Horizons
Horizon: Null Hypersurface (light‐like surface) Any information can come from the other side of the horizon (classically)
Black hole horizon (including acoustic BH)
Even light cannot come out of the BH horizon.
Escape velocity froma star M at radius R → c (speed of light)
Critical radius (Schwarzshild radius)
de Sitter horizon= cosmological horizon(accelerating universe)
Rindler horizon =accelerating horizon
observerdependent
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RL
F
P
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RL
F
P
horizon
Classically causality plays an important role to characterize the horizon.
L RLeft modes (ingoing modes) aredecoupled from the outer world.
Quantum mechanically, gravitational and gauge anomaly appears.Flux of the Hawking radiation saves it.
Horizon thermodynamics
Black hole:
Acceleratingobserver Unruh effect
a =acceleration
κ =surface gravityat horizon
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Bardeen Carter Hawking (73) + Hawking(76) + Beckenstein (74) + . . .
Stationary black holes satisfy Equilibrium Thermodynamics Laws
0th law : Surface gravity is constant over the horizon(temperature is constant in an equilibrium state)
1st law : Energy conservation between the horizon and r=∞
Local version of 1st law
Killing vector generating horizon
It is easily proved by using Raychaudhuri eq. and Einstein eq.
: Energy flow across horizon
Note that the proof makes no reference to spatial infinity, and applicable to local horizon.(Normalization of killing vector is cancelled in dE and T. )
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2nd law : (generalized 2nd law)
no matter what happens (including negative energy flow into BH)
Various proofs : (a proof by Wald)
BH
Outer region is described by Hartle‐Hawking state (= thermal).
Energy: Entropy:
small perturbation
Clausius relation (entropy is maximized for the thermalized state)
And integrate over the horizon (using 1st law)
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Chapter 2 Non‐equilibrium Thermodynamics
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Equilibrium thermodynamics
1st law (energy conservation)
2nd law (entropy increase)
Hydrodynamics Based on “local equilibrium”and “equation of states”
Fluctuations around the equilibrium
transport coefficients
Einstein (Brownian motion)
In order to prove the reality of atoms,Einstein proposed many ways to estimateAvogadro Number using fluctuations.
Fluctuation – Dissipation Theorem
Linear response theorem
(Non‐equilibrium) fluctuation theorem(Jarzynski, Crooks, … )
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Non‐equilibrium Fluctuation theorem and Jarzynski equality
Classifications of out‐of‐equilibrium states
(1) NETS (non‐equilibrium transient state) equilibrium state → switch on an external perturbation
→ system returns to a new equilibrium
(2) NESS (non‐equilibrium steady‐state) :steady current in constant electric fielddriven by external force (like a constant electric field)
→ energy is dissipated (heat) like Joule heat of electric current→ stationary entropy production
(3) NEAS (non‐equilibrium aging state) slow relation = very small heat dissipation glassy system etc.
Fluctuation theorems can be applied to these cases.
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Jarzynski Equality (97)
Equilibriumat t=0
change of parameter
W: mechanical work exerted on the system by perturbation
Surprise (1) : lhs = an average of work by a non‐equilibrium process over various initial statesrhs = difference of free energy at equilibrium.
out of equilibrium
Surprise (2)Dissipated work (entropy production)
or2nd law of thermodynamics (entropy increase law)
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Surprise (3) :
An averaged dissipated work is positive.But, if we look at each microscopic process, negative dissipated work is necessary !
( violation of 2nd law at the microscopic level )
Crooks Fluctuation Theorem (2000)
change of parameter
Forward
Reversed
Jarzynski equality
Integrate over
Surprise (4) Linear response th., FDT, or Onsager reciprocal relation etc. are derived!
Surprise (5) There are several (mesoscopic) experiments to show theses equalities!
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Proof of Crooks fluctuation theorem Very easy, almost trivial
A system described by configuration
Sequence of configurations
:Probability that the system is in config. at time
Markovian process:
transition prob
Note: Ratio of transition prob. is related to the entropy difference;
Local detailed balance
Probability for a sequence of config
See e.g.Ritort’s review(07)
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reversed change of parameterreversed sequence of config.
Ratio:
Assume that the initial state is in an equilibrium state
Define the total dissipation rate as
Initial condition
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Probability to produce a total dissipation along the forward protocol is
Note:
q.e.d
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Chapter 3Fluctuation Theorem for BH
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Fluctuation theorems for black hole horizons
BHArea = A
outer system(detector or matter)
entangledADM mass Mis fixed.
How can we describe such a state?
= Einstein Hilbert action
Gravity is a constrained system. → Does Hamiltonian always vanish? → NO
Wheeler DeWitt eq.
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Regge Teitelboim (74)Teitelboim (95)
Variations of the action do not vanish if there are boundaries.
(1) Spatial infinity
It vanishes if we fix the ADM mass.But if we want to fix the time‐interval at spatial infinity,we need to Legendre transform
Boundary variables must be considered as independent variables.
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(2) Horizon is another boundary
If area of the horizon is fixed, it vanishes.
For Euclidean case, Gibbons HawkingBlack hole entropy
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BHArea = A
outer system(detector or matter)
entangledADM mass Mis fixed.
What is the transition probability from one configuration to another?
We should always impose the ingoing boundary condition at horizon.( = initial state is in the Unruh vacuum for the outgoing modes)
Regularity at the horizon
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Kruskal coordinate
On the other hand, the reversed amplitude is given by
Massar ,Parentani (99)Kraus Wilczek (95)
Note: if we useordinary result of Hawking radiation rate
: heat transfer to outer region
Transition amplitude from configuration C with BH area A to C’ with A’ is evaluated by a first order perturbation of the interaction Hamiltonian,
mediate the interaction via Hawking radiation
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Ratio of transition probabilities for sequences of configurations of black holes
with an initial condition for the outer region
Fluctuation theorem for Black holes
Jarzynski equality for Black holes
Generalized 2nd law for Black holes
Entropy decreasing process is microscopically necessary.(Microscopic violation of 2nd law)
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Chapter 4Conclusions and . . . A Fantasy
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Conclusions
We have applied the fluctuation theorem and Jarzynski relation to Black hole systems (also applicable to any local horizon)
→ (1) ratio of the transition amplitude is given by
Detailed balance → entropy of BHHawking radiation(backreaction is included)
(2) Applying the method in proving Crooks fluctuation theorem, we have obtained
total entropy
(3) We have proved the generalized 2nd law of black holes
It is important, however, that the GSL should be violated for eachmicroscopic process to satisfy the Jarzynski relation.
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Discussions (or a fantasy? )
(1) What is an analog of Avogadro number in gravity?
・ Avogadro number cannot be determined within (local) equilibrium thermodynamics.
Various methods (i) Maxwell distribution (Loschmidt) D‐brane dynamics ??(ii) Planck’ s radiation law Hawking radiation(iii) Brownian motion (Einstein) Brownian motion
near horizonsFluctuation Fluctuations of space‐time ?
number of particles per mol number of microstates per unit area
Avogadro numberPlanck number (or Beckenstein)
Is the space‐time made of atoms ???Is the gravity entropic force ????
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(2) Origin of irreversibility (or Origin of dissipation)
H‐theorem, Loschmidt, Zermelo,Maxwell daemon
Can we manipulate the ‘heat bath’(source of dissipation) at our will?
Non‐equilibrium fluctuation theorem2nd law and its microscopic violation
Hawking, Beckenstein, …
“Information paradox “
Dissipation = loss of entanglementHow can we take the effect of backreaction?
Entropy = entanglement?(Even Rindler horizon can have entropy)
(3) Einstein equation is a kind of equilibrium thermodynamic equation.
T. Jacobson Derivation of Einstein eq
But, Clausius inequality Deviation from Einstein eq ??
Black hole is the maximum entropy state. (Bousso bound)
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