Unitary and non-unitary manipulations of qubit-bath entanglement: Non-Markov qubit cooling

Guy Bensky*, Goren Gordon, David Gelbwaser-Klimovsky, D. D.Bhaktavatsala Rao, Noam Erez, Gershon Kurizki

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Initialization of quantum logic operations makes it imperative to cool down the information-carrying qubits as much and as fast as possible, so as to purify their state, or at least their ensemble average. Yet, the limit on the speed of existing cooling schemes is either the duration of the qubit equilibration with its bath or the decay time of an auxiliary state to one of the qubit states. Here we show that highly-frequent phase-shifts or measurements of the state of thermalized qubits can be designed to affect the qubit-bath entanglement so that the qubits undergo cooling, well before they re-equilibrate with the bath and without resorting to auxiliary states. These processes can be used in principally novel, advantageous, cooling schemes to assist quantum logic operations.

Original languageEnglish
Pages (from-to)607-617
Number of pages11
JournalQuantum Information Processing
Issue number6
StatePublished - Dec 2009
Externally publishedYes


  • Non-Markovian processes
  • Quantum cooling
  • Quantum information processing
  • Quantum thermodynamic control
  • Qubit initialization


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