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SUMMARY:The Second Laws of Quantum Thermodynamics - Oppenheim\, J (Univers
 ity College London)
DTSTART:20131024T130000Z
DTEND:20131024T140000Z
UID:TALK48457@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:The second law of thermodynamics tells us which state transfor
 mations are so statistically unlikely that they are effectively forbidden\
 , and applies to systems composed of many particles. However\, using tools
  from quantum information theory\, we are seeing that one can make sense o
 f thermodynamics in the regime where we only have a small number of partic
 les interacting with a heat bath\, or when we have highly correlated syste
 ms and wish to make non-statistical statements about them. Is there a seco
 nd law of thermodynamics in this regime? Here\, we find that for processes
  which are cyclic or very close to cyclic\, the second law for microscopic
  or highly correlated systems takes on a very different form than it does 
 at the macroscopic scale\, imposing not just one constraint on what state 
 transformations are possible\, but an entire family of constraints. In par
 ticular\, we find a family of quantum free energies which generalise the t
 raditional ones\, and show that they can never increase. The ordinary seco
 nd law corresponds to the non-increasing of one of these free energies\, w
 ith the remainder\, imposing additional constraints on thermodynamic trans
 itions of quantum systems. We further find that there are three regimes wh
 ich govern which family of second laws govern state transitions\, dependin
 g on how cyclic the thermodynamical process is. In one regime one can caus
 e an apparent violation of the usual second law through a process of embez
 zling work from a large system which remains arbitrarily close to its orig
 inal state. By making precise the definition of thermal operations\, the l
 aws of thermodynamics take on a simple form with the first law defining th
 e class of thermal operations\, the zeroeth law emerging as a unique equil
 ibrium condition\, and the remaining laws being a monotonicity property of
  our generalised free energies based on the Renyi-divergence. The derivati
 ons use tools from majorisation theory.\n\n
LOCATION:Seminar Room 1\, Newton Institute
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