Unitary Work Extraction, Quantum Batteries and Powerful Driving

演讲人: Felix Binder Nanyang Technological University (Mile Gu's group)
时间: 2017-10-30 11:00-2017-10-30 12:30
地点:MMW S327

One of the central aims of the emerging field of 'quantum thermodynamics' is to uncover thermodynamic effects which are of a genuinely quantum nature. Quantum mechanics may provide a thermodynamic advantage but also an additional hurdle compared to classical physics. While it has been demonstrated that entangling operations lead to some increase in extractable work I will show that, when power is considered, a much stronger enhancement may be achieved. More specifically, I will compare the optimal power of charging an array of N quantum batteries in parallel to entangling charging of the same array. The ratio between both is called quantum advantage. It can be shown to be upper bounded by √N and this bound is achievable even when driving between separable states.

Taking the simplest possible model of a quantum battery – a wit (short for ‘work bit’), an optimal charging protocol is readily derived. Extending the analysis again to an array of N wits, I will demonstrate quantum advantage with this concrete example. Interestingly, the upper bound may be achieved by entangling operations even in the absence of entanglement at all times during the evolution.

Finally, I will discuss the extension of the results to Hamiltonians with few-body interactions.



Dr. Felix did the undergraduate at LMU Munich (physics diploma) and studied at Oxford for the thesis with Dieter Jaksch as 'Measures of mode entanglement'. In Munich, he also received a degree in Digital Technology Management. From 2012-2016, he did his Ph. D program in Oxford with Vlatko Vedral as 'Work, Heat, and Power of Quantum Processes'. Since 2016, He is in Singapore, at NTU, as a research fellow in Mile Gu's group.