Achievable Polarization for Heat-Bath Algorithmic Cooling

Nayeli Azucena Rodríguez-Briones and Raymond Laflamme
Phys. Rev. Lett. 116, 170501 – Published 25 April 2016
PDFHTMLExport Citation

Abstract

Pure quantum states play a central role in applications of quantum information, both as initial states for quantum algorithms and as resources for quantum error correction. Preparation of highly pure states that satisfy the threshold for quantum error correction remains a challenge, not only for ensemble implementations like NMR or ESR but also for other technologies. Heat-bath algorithmic cooling is a method to increase the purity of a set of qubits coupled to a bath. We investigated the achievable polarization by analyzing the limit when no more entropy can be extracted from the system. In particular, we give an analytic form for the maximum polarization achievable for the case when the initial state of the qubits is totally mixed, and the corresponding steady state of the whole system. It is, however, possible to reach higher polarization while starting with certain states; thus, our result provides an achievable bound. We also give the number of steps needed to get a specific required polarization.

  • Figure
  • Figure
  • Figure
  • Figure
  • Figure
  • Received 18 December 2014

DOI:https://doi.org/10.1103/PhysRevLett.116.170501

© 2016 American Physical Society

Physics Subject Headings (PhySH)

Quantum Information, Science & Technology

Authors & Affiliations

Nayeli Azucena Rodríguez-Briones1,2 and Raymond Laflamme1,2,3,4

  • 1Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
  • 2Department of Physics & Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
  • 3Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, Ontario N2L 2Y5, Canada
  • 4Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8, Canada

Article Text (Subscription Required)

Click to Expand

Supplemental Material (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 116, Iss. 17 — 29 April 2016

Reuse & Permissions
Access Options

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Letters

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×