SAMOP 2021 – scientific programme
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QI: Fachverband Quanteninformation
QI 7: Quantum Information: Applications
QI 7.2: Talk
Wednesday, September 22, 2021, 11:00–11:15, H4
Cyclic cooling of quantum systems at the saturation limit — •Durga Dasari1, Sadegh Raeisi2, and Joerg Wrachtrup1 — 13. Physics Institute, University of Stuttgart, Stuttgart, GERMANY — 2Department of Physics, Sharif University of Technology, Tehran, IRAN
The achievable bounds of cooling quantum systems, and the possibility to violate them is not well-explored experimentally. For example, among the common methods to enhance spin polarization (cooling), one utilizes the low temperature and high-magnetic field condition or employs a resonant exchange with highly polarized spins. The achievable polarization, in such cases, is bounded either by Boltzmann distribution or by energy conservation. Heat-bath algorithmic cooling schemes (HBAC), on the other hand, have shown the possibility to surpass the physical limit set by the energy conservation and achieve a higher saturation limit in spin cooling. Despite, the huge theoretical progress, and few principle demonstrations, neither the existence of the limit nor its application in cooling quantum systems towards the maximum achievable limit have been experimentally verified. Here, we show the experimental saturation of the HBAC limit for single nuclear spins, beyond any available polarization in solid-state spin system, the Nitrogen-Vacancy centers in diamond. We benchmark the performance of our experiment over a range of variable reset polarizations (bath temperatures), and discuss the role of quantum coherence in HBAC.