Exponential improvement for quantum cooling through finite-memory effects

• URL: http://arxiv.org/abs/2004.00323v2
• Date: Thu, 5 Nov 2020 10:37:35 GMT
• Title: Exponential improvement for quantum cooling through finite-memory effects
• Authors: Philip Taranto, Faraj Bakhshinezhad, Philipp Sch\"uttelkopf, Fabien Clivaz, and Marcus Huber
• Abstract summary: We study the effects of memory on quantum cooling. For qubits, our bound coincides with that of heat-bath algorithmic cooling. We describe the adaptive step-wise optimal protocol that outperforms all standard procedures.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Practical implementations of quantum technologies require preparation of states with a high degree of purity---or, in thermodynamic terms, very low temperatures. Given finite resources, the Third Law of thermodynamics prohibits perfect cooling; nonetheless, attainable upper bounds for the asymptotic ground state population of a system repeatedly interacting with quantum thermal machines have been derived. These bounds apply within a memoryless (Markovian) setting, in which each refrigeration step proceeds independently of those previous. Here, we expand this framework to study the effects of memory on quantum cooling. By introducing a memory mechanism through a generalized collision model that permits a Markovian embedding, we derive achievable bounds that provide an exponential advantage over the memoryless case. For qubits, our bound coincides with that of heat-bath algorithmic cooling, which our framework generalizes to arbitrary dimensions. We lastly describe the adaptive step-wise optimal protocol that outperforms all standard procedures.

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