Algorithmic cooling of nuclear spins using long-lived singlet order

Bogdan A. Rodin, Christian Bengs, Alexey S. Kiryutin, Kirill F. Sheberstov, Lynda J. Brown, Richard C. D. Brown, Alexandra V. Yurkovskaya, Konstantin L. Ivanov, Malcolm H. Levitt

Research output: Contribution to journalArticlepeer-review

Abstract

Algorithmic cooling methods manipulate an open quantum system in order to lower its temperature below that of the environment. We achieve significant cooling of an ensemble of nuclear spin-pair systems by exploiting the long-lived nuclear singlet state, which is an antisymmetric quantum superposition of the "up" and "down" Zeeman states. The effect is demonstrated by nuclear magnetic resonance experiments on a molecular system containing a coupled pair of near-equivalent C-13 nuclei. The populations of the system are subjected to a repeating sequence of cyclic permutations separated by relaxation intervals. The long-lived nuclear singlet order is pumped well beyond the unitary limit. The pumped singlet order is converted into nuclear magnetization which is enhanced by 21% relative to its thermal equilibrium value.

Original languageEnglish
Number of pages16
JournalJournal of Chemical Physics
Volume152
Issue number16
DOIs
Publication statusPublished - 30 Apr 2020

Keywords

  • NMR POPULATION-INVERSION
  • STATE
  • FREQUENCIES
  • LIFETIMES
  • SYSTEMS
  • PHASES
  • SIGNS

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