Entanglement of a coarse grained quantum field in the expanding universe

被引：12

作者：

Nambu, Yasusada ^{[1
]}

Ohsumi, Yuji ^{[1
]}

机构：

[1] Nagoya Univ, Dept Phys, Grad Sch Sci, Chikusa Ku, Nagoya, Aichi 4648602, Japan

来源：

PHYSICAL REVIEW D | 2009年 / 80卷 / 12期

关键词：

CONTINUOUS VARIABLE SYSTEMS; SEPARABILITY CRITERION; INFLATIONARY UNIVERSE; COSMOLOGICAL PERTURBATIONS; CLASSICAL TRANSITION; MIXED STATES; SCALAR FIELD; FLUCTUATIONS; DECOHERENCE; SPACE;

D O I：

10.1103/PhysRevD.80.124031

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We investigate the entanglement of a quantum field in the expanding universe. By introducing a bipartite system using a coarse-grained scalar field, we apply the separability criterion based on the partial transpose operation and numerically calculate the bipartite entanglement between separate spatial regions. We find that the initial entangled state becomes separable or disentangled after the spatial separation of two points exceed the Hubble horizon. This provides the necessary conditions for the appearance of classicality of the quantum fluctuation. We also investigate the condition of classicality that the quantum field can be treated as the classical stochastic variables.

引用

页数：11

共 21 条

[1] Extremal entanglement and mixedness in continuous variable systems [J].

Adesso, G ;

Serafini, A ;

Illuminati, F .

PHYSICAL REVIEW A, 2004, 70 (02) :022318-1

[2] Determination of continuous variable entanglement by purity measurements [J].

Adesso, G ;

Serafini, A ;

Illuminati, F .

PHYSICAL REVIEW LETTERS, 2004, 92 (08)

[3] INFLATION AND SQUEEZED QUANTUM STATES [J].

ALBRECHT, A ;

FERREIRA, P ;

JOYCE, M ;

PROKOPEC, T .

PHYSICAL REVIEW D, 1994, 50 (08) :4807-4820

[4]

Bell J.S., 1964, PHYSICS, V1, P195, DOI [10.1103/Physics-PhysiqueFizika.1.195, DOI 10.1103/PHYSICSPHYSIQUEFIZIKA.1.195, 10.1103/PhysicsPhysiqueFizika.1.195]

[5] CLASSICAL PERTURBATIONS FROM DECOHERENCE OF QUANTUM FLUCTUATIONS IN THE INFLATIONARY UNIVERSE [J].