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Engineering and Control of Quantum Machines
Friday, 28th June 2019
Location: Technische Universität Berlin
Main building, Room H
3005
Straße des 17. Juni 135, 10623 Berlin
Guests are welcome!
Programme
Friday, 28. June 2019
15:00 
PIQUE: a
new Framework for Quantum Systems Engineering
Prof. Archana Kamal, Umass
Lowell, USA 
15:50  Coffee
Break 
16:10  Reservoir Engineering using
Quantum Optimal Control for Qubit Reset
Daniel
Basilewitsch, Universität Kassel

16:35 
Quantum Simulation of nonMarkovianity Using
the Quantum Zeno Effect
Sabrina Patsch, Universität Kassel

17:00  Informal gettogether
("Stammtisch") 
Abstracts
Highfidelity quantum state preparation, manipulation and measurement are the three cornerstones of any quantum information processing platform. In this talk I will describe a new paradigm called PIQUE (for ParametricallyInduced QUantum Engineering), which tackles all three challenges in a unified framework employing parametricallymodulated interactions between quantum systems. In the first part of my talk, I will focus on how parametricallyinduced interactions have stimulated new functionalities in the field of nonreciprocal amplification, and signal processing. In the second part of the talk, I will discuss how such interactions can be leveraged for quantum state engineering, specifically quantum ground state cooling, highfidelity dissipative control and entanglement generation.
Reservoir Engineering using Quantum Optimal Control for Qubit Reset
Daniel Basilewitsch, Uni Kassel
We determine how to optimally reset a superconducting qubit which interacts with a thermal environment in such a way that the coupling strength is tunable. Describing the system in terms of a timelocal master equation with time dependent decay rates and using quantum optimal control theory, we identify temporal shapes of tunable level splittings which maximize the efficiency of the reset protocol in terms of duration and error. Timedependent level splittings imply a modification of the systemenvironment coupling, varying the decay rates as well as the Lindblad operators. Our approach thus demonstrates efficient reservoir engineering employing quantum optimal control. We find the optimized reset strategy to consist in maximizing the decay rate from one state and driving nonadiabatic population transfer into this strongly decaying state.
Quantum Simulation of nonMarkovianity Using the
Quantum Zeno Effect
Sabrina Patsch, Uni Kassel
A watched quantum arrow does not move. This effect, referred to as the quantum Zeno effect, arises from a frequent measurement of a quantum system’s state. In more general terms, the evolution of the quantum system can be confined to a subspace of the system’s Hilbert space leading to quantum Zeno dynamics. Resulting from the measurement process, a source of dissipation is introduced into the systems dynamics. However, differently from a generic open quantum system, we can choose the strength of the dissipation by changing the parameters of the Zeno measurement. We capitalise on the property of tunable dissipation to create a quantum simulator for open quantum systems with Markovian and nonMarkovian dynamics. We show how to tune the amount of dissipation and the nonMarkovianity independently from each other and derive a Lindblad master equation to describe the evolution in the Markovian limit. We demonstrate the experimental feasibility of the proposed quantum simulator using a setup in the framework of cavity QED where the considered quantum system are photons inside a cavity being subject to an indirect measurement using circular Rydberg atoms.