Coarse graining and decoherence in quantum field theory

Lombardo, Fernando C.; Mazzitelli, Francisco D.

doi:10.1103/physrevd.53.2001

Cited by 117 publications

(173 citation statements)

References 29 publications

(27 reference statements)

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“…Various arguments and calculations suggesting that a form of such environmental decoherence can indeed occur for inflationary perturbations have been put forward in [8,9,10,11,12,13,14,15,16]. In [9,10,11,12,13,14,16], the environment is taken to consist of the short wavelength modes which are coupled to the long wavelength modes via non-linear couplings. In this paper, we point out that the decoherence of cosmological perturbations can occur in a precisely defined dynamical setting if the role of the environment is played by unobservable isocurvature perturbations generated during multi-field inflation.…”

Section: Introductionmentioning

confidence: 99%

Decoherence from isocurvature perturbations in inflation

Prokopec

Rigopoulos²

2007

J. Cosmol. Astropart. Phys.

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We discuss the possible role of isocurvature perturbations for the quantum decoherence of the curvature perturbation during inflation. We point out that if the inflaton trajectory in field space is curved, the adiabatic mode is generically coupled to the isocurvature mode and thus tracing out the latter can cause the curvature perturbation to decohere. We explicitly investigate this suggestion in a model of inflation with two decoupled massive fields and find that decoherence is effective for a wide range of mass ratios. In particular, we calculate the entanglement entropy for this model and show that it grows after horizon exit, providing a quantitative measure for decoherence.

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Section: Introductionmentioning

confidence: 99%

Decoherence from isocurvature perturbations in inflation

Prokopec

Rigopoulos²

2007

J. Cosmol. Astropart. Phys.

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“…In this way, we can see that the above expression is formally equivalent to the definition of the influence functional (see Ref. [11] for details). Thus, we may write…”

Section: The Decoherence Functionalmentioning

confidence: 87%

“…will form an environment whose coarse-graining makes the long-wavelength modes decohere [11]. In practice, the boundary between stable and unstable is not crucially important, provided there is time enough for the power in the field fluctuations to be firmly in the long-wavelength modes.…”

Section: Evolution Of the Density Matrixmentioning

confidence: 99%

How Phase Transitions Induce Classical Behaviour

Rivers

Lombardo

2005

Int J Theor Phys

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We continue the analysis of the onset of classical behaviour in a scalar field after a continuous phase transition, in which the system-field, the long wavelength order parameter of the model, interacts with an environment, of its own short-wavelength modes and other fields, neutral and charged, with which it is expected to interact. We compute the decoherence time for the system-field modes from the master equation and directly from the decoherence functional (with identical results). In simple circumstances the order parameter field is classical by the time the transition is complete. 03.70.+k, 05.70.Fh, 03.65.Yz

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“…Several works show that EID can solve the quantum-classical transition of the universe, by separating the different degrees of freedom in system and environment. Since there is no a standard way to divide the universe, some authors take the inflaton as a system and the gravitons as the environment [67], while other authors divide the universe between long and short frequencies [68].…”

Section: Decoherence Without Decoherencementioning

confidence: 99%

Decoherence: A Closed-System Approach

2013

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The aim of this paper is to review a new perspective about decoherence, according to which formalisms originally devised to deal just with closed or open systems can be subsumed under a closed-system approach that generalizes the traditional account of the phenomenon. This new viewpoint dissolves certain conceptual difficulties of the orthodox open-system approach but, at the same time, shows that the openness of the quantum system is not the essential ingredient for decoherence, as commonly claimed. Moreover, when the behavior of a decoherent system is described from a closed-system perspective, the account of decoherence turns out to be more general than that supplied by the open-system approach, and the quantum-to-classical transition defines unequivocally the realm of classicality by identifying the observables with classical-like behavior.

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Coarse graining and decoherence in quantum field theory

Cited by 117 publications

References 29 publications

Decoherence from isocurvature perturbations in inflation

Decoherence from isocurvature perturbations in inflation

How Phase Transitions Induce Classical Behaviour

Decoherence: A Closed-System Approach

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