TY - JOUR

T1 - Quantum evolution leading to classicality

T2 - a concrete example

AU - Lochan, Kinjalk

AU - Parattu, Krishnamohan

AU - Padmanabhan, T.

N1 - Publisher Copyright:
© 2014, Springer Science+Business Media New York.

PY - 2015/1

Y1 - 2015/1

N2 - Can certain degrees of freedom of a closed physical system, described by a time-independent Hamiltonian, become more and more classical as they evolve from 1 some state? This question is important because our universe seems to have done just that! We construct an explicit, simple, example of such a system with just two degrees of freedom, of which one achieves ‘spontaneous classicalization’. It starts from a quantum state and under the usual Hamiltonian evolution, becomes more and more classical (in a well-defined manner in terms of the Wigner function) as time progresses. This is achieved without the usual procedures of integrating out a large number of environmental degrees of freedom or conventional decoherence. We consider different ranges of parameter space and identify the conditions under which spontaneous classicalization occurs in our model. The mutual interaction between the sub-systems of a larger system can indeed drive some of the subsystems to a classical configuration, with a phase space trajectory of evolution. We also argue that the results of our toy model may well be general characteristics of certain class of interacting systems. Several implications are discussed.

AB - Can certain degrees of freedom of a closed physical system, described by a time-independent Hamiltonian, become more and more classical as they evolve from 1 some state? This question is important because our universe seems to have done just that! We construct an explicit, simple, example of such a system with just two degrees of freedom, of which one achieves ‘spontaneous classicalization’. It starts from a quantum state and under the usual Hamiltonian evolution, becomes more and more classical (in a well-defined manner in terms of the Wigner function) as time progresses. This is achieved without the usual procedures of integrating out a large number of environmental degrees of freedom or conventional decoherence. We consider different ranges of parameter space and identify the conditions under which spontaneous classicalization occurs in our model. The mutual interaction between the sub-systems of a larger system can indeed drive some of the subsystems to a classical configuration, with a phase space trajectory of evolution. We also argue that the results of our toy model may well be general characteristics of certain class of interacting systems. Several implications are discussed.

KW - Classical limit

KW - Cosmology

KW - Quantum evolution

KW - Universe

UR - http://www.scopus.com/inward/record.url?scp=84920409551&partnerID=8YFLogxK

U2 - 10.1007/s10714-014-1841-9

DO - 10.1007/s10714-014-1841-9

M3 - Article

AN - SCOPUS:84920409551

VL - 47

JO - General Relativity and Gravitation

JF - General Relativity and Gravitation

SN - 0001-7701

IS - 1

ER -