Physics MS Thesis Defense by Angsar Manatuly

KOÇ UNIVERSITY

GRADUATE SCHOOL OF SCIENCES & ENGINEERING

PHYSICS

MS THESIS DEFENSE BY ANGSAR MANATULY

Title: Multi-Qubit Fuels.

Speaker: Angsar Manatuly.

Time: June 6th, 2018, 16:00

Place: ENG 127

Koç University

Rumeli Feneri Yolu

Sariyer, Istanbul

Thesis Committee Members:

Prof. Dr. Özgür E. Müstecaplıoğlu (Advisor, Koç University)

Assoc. Prof. Alkan Kabakçıoğlu (Koç University)

Asst. Prof. Dr. Ilke Ercan (Boğaziçi University)

Abstract:

In the last decade, there has been a major development to understand the properties of non-thermal baths, which can be used as a fuel for quantum heat engines. The efficiency of such engines can surpass the classical Carnot bound, and these engines can even operate with a single heat bath and an information reservoir. Quantum coherent particle clusters are one of the examples of such non-thermal baths. Decoherence is the major obstacle for utilizing the advantages of quantum coherent fuels. Increasing the number of particles and thus the amount of coherence can overcome this obstacle. However, the analytical studies of such non-thermal reservoirs were investigated only up to three coherent particles, and for the general coherent multi-particle fuels results were obtained numerically. In this thesis, we analytically show how coherences are classified in N-qubit clusters in terms of their interaction with the working fluid. We demonstrate that these coherent N-qubit clusters can thermalize, coherently drive the working mode, or can be used to engineer effective squeezed thermal bath. We show that the steady-state temperature of the working mode can scale linearly or quadratically with the number of the qubits in the cluster. We also construct an Otto engine using our model and show that we can increase efficiency bound. Finally, we propose how we can implement our model in a circuit-QED platform.