Different instances of time as different quantum modes: Quantum states across space-time for continuous variables

Zhang，Tian1,2; Dahlsten，Oscar1,3,4; Vedral，Vlatko1,5,6,7

2020

10.1088/1367-2630/ab6b9f

NEW JOURNAL OF PHYSICS   影响因子和分区

1367-2630

Space-time is one of the most essential, yet most mysterious concepts in physics. In quantum mechanics it is common to understand time as a marker of instances of evolution and define states around all the space but at one time; while in general relativity space-time is taken as a combinator, curved around mass. Here we present a unified approach on both space and time in quantum theory, and build quantum states across spacetime instead of only on spatial slices. We no longer distinguish measurements on the same system at different times with measurements on different systems at one time and construct spacetime states upon these measurement statistics. As a first step towards non-relativistic quantum field theory, we consider how to approach this in the continuous-variable multi-mode regime. We propose six possible definitions for spacetime states in continuous variables, based on four different measurement processes: quadratures, displaced parity operators, position measurements and weak measurements. The basic idea is to treat different instances of time as different quantum modes. They are motivated by the pseudo-density matrix formulation among indefinite causal structures and the path integral formalism. We show that these definitions lead to desirable properties, and raise the differences and similarities between spatial and temporal correlations. An experimental proposal for tomography is presented, construing the operational meaning of the spacetime states.

continuous variables quantum correlations quantum states across spacetime temporal modes

SCI ; EI

英语

其他

National Research Foundation, Prime Minister'sOffice, Singapore[NRF-CRP14-2014-02]

Physics

Physics, Multidisciplinary

WOS:000537571500004

IOP PUBLISHING LTD

20201308355701

Quantum optics

Light/Optics:741.1 ; Quantum Theory; Quantum Mechanics:931.4 ; Gravitation, Relativity and String Theory:931.5

PHYSICS

2-s2.0-85082308246

Scopus

1.Department of Physics,Clarendon Laboratory,University of Oxford,Oxford,Parks Road,OX1 3PU,United Kingdom
2.Perimeter Institute for Theoretical Physics,Waterloo,31 Caroline Street North,N2L 2Y5,Canada
3.Institute for Quantum Science and Engineering,Department of Physics,Southern University of Science and Technology (SUSTech),Shenzhen,518055,China
4.London Institute for Mathematical Sciences,London,35a South Street, Mayfair,W1K 2XF,United Kingdom
5.Centre for Quantum Technologies,National University of Singapore,Singapore,Block S15, 3 Science Drive 2,117543,Singapore
6.Department of Physics,National University of Singapore,Singapore,2 Science Drive 3,117542,Singapore
7.I.S.I. Istituto Interscambio Scientifico,Torino TO,Via Chisola, 5,I-10126,Italy

Zhang，Tian,Dahlsten，Oscar,Vedral，Vlatko. Different instances of time as different quantum modes: Quantum states across space-time for continuous variables[J]. NEW JOURNAL OF PHYSICS,2020,22(2).

Zhang，Tian,Dahlsten，Oscar,&Vedral，Vlatko.(2020).Different instances of time as different quantum modes: Quantum states across space-time for continuous variables.NEW JOURNAL OF PHYSICS,22(2).

Zhang，Tian,et al."Different instances of time as different quantum modes: Quantum states across space-time for continuous variables".NEW JOURNAL OF PHYSICS 22.2(2020).