Dynamics and thermodynamics of a central spin immersed in a spin bath

Chiranjib Mukhopadhyay, Samyadeb Bhattacharya, Avijit Misra, and Arun Kumar Pati
Phys. Rev. A 96, 052125 – Published 20 November 2017

Abstract

An exact reduced dynamical map along with its operator sum representation is derived for a central spin interacting with a thermal spin environment. The dynamics of the central spin shows high sustainability of quantum traits such as coherence and entanglement in the low-temperature regime. However, for sufficiently high temperature and when the number of bath particles approaches the thermodynamic limit, this feature vanishes and the dynamics closely mimics Markovian evolution. The properties of the long-time-averaged state and the trapped information of the initial state for the central qubit are also investigated in detail, confirming that the nonergodicity of the dynamics can be attributed to the finite temperature and finite size of the bath. It is shown that if a certain stringent resonance condition is satisfied, the long-time-averaged state retains quantum coherence, which can have far reaching technological implications in engineering quantum devices. An exact time-local master equation of the canonical form is derived. With the help of this master equation, the nonequilibrium properties of the central spin system are studied by investigating the detailed balance condition and irreversible entropy production rate. The result reveals that the central qubit thermalizes only in the limit of very high temperature and large number of bath spins.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
5 More
  • Received 5 June 2017
  • Revised 18 October 2017

DOI:https://doi.org/10.1103/PhysRevA.96.052125

©2017 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & TechnologyAtomic, Molecular & OpticalGeneral Physics

Authors & Affiliations

Chiranjib Mukhopadhyay1,*, Samyadeb Bhattacharya1,†, Avijit Misra2,‡, and Arun Kumar Pati1,§

  • 1Harish-Chandra Research Institute, Allahabad 211019, India and Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400 085, India
  • 2Optics and Quantum Information Group, The Institute of Mathematical Sciences, H.B.N.I., C.I.T. campus, Taramani, Chennai 600113, India

  • *chiranjibmukhopadhyay@hri.res.in
  • samyadebbhattacharya@hri.res.in
  • avijitm@imsc.res.in
  • §akpati@hri.res.in

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 96, Iss. 5 — November 2017

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review A

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×