How to cool a Quantum Bit using tools from Quantum Information Theory

Friday, June 19, 2020 10:00 am - 10:00 am EDT (GMT -04:00)

Quantum information science gives us an effective language to describe physical phenomena in terms of the evolution of information. This information paradigm allows us to bring new solutions to old problems, for example to the task of cooling a physical system. While we usually think of cooling as putting a hot system inside a refrigerator, or making contact with a cold bath that cools through random collisions with cold molecules, we can
instead think of cooling as processing information. A natural question that arises is, then, can we use tools from quantum information processing to turn cooling from a random process into a deterministic one, even at the microscopic level? This is exactly what heat-bath algorithmic cooling protocols achieve. Such algorithms can efficiently reach lower temperatures than conventional cooling techniques and aid in the preparation of pure states out of mixed ones, an important task for quantum technologies.

In this talk, I will first review the basic ideas of algorithmic cooling1 and then give the analytical solution for the achievable cooling limits of standard heat-bath algorithmic cooling2. Then, I will show how these limits can be circumvented by taking advantage of quantum
correlations created both from thermalization with the heat-bath and from internal interactions3, 4.

References:
1 DK Park, NA Rodriguez-Briones , G Feng, R Rahimi, J Baugh, and R Laflamme. “Heat bath algorithmic cooling with spins:
review and prospects”. A Book Chapter in Electron Spin Resonance (ESR) Based Quantum Computing (pp. 227-255).
Springer, New York, NY. (2016)
2 NA Rodríguez-Briones , and R Laflamme. "Achievable polarization for heat-bath algorithmic cooling."
Phys. Rev. Lett. 116.17 (2016): 170501.
3 NA Rodriguez-Briones , J Li, X Peng, T Mor, Y Weinstein, and R Laflamme. "Heat-bath algorithmic cooling with correlated
qubit-environment interactions." New Journal of Phys. 19, no. 11 (2017): 113047.
4 NA Rodríguez-Briones , E Martín-Martínez, A Kempf, and Raymond Laflamme. "Correlation-enhanced algorithmic cooling."
Phys. Rev. Lett. 119, no. 5 (2017): 050502.


Nayeli Rodriguez Briones is presenting this talk as a degree milestone in PhD Quantum Information.