Observation of the Bloch-Siegert shift in a driven quantum-to-classical transition

Pietikäinen, I., Danilin, S. , Kumar, K.S., Vepsäläinen, A., Golubev, D.S., Tuorila, J. and Paraoanu, G.S. (2017) Observation of the Bloch-Siegert shift in a driven quantum-to-classical transition. Physical Review B, 96(2), 020501(R). (doi: 10.1103/physrevb.96.020501)

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We show that the counter-rotating terms of the dispersive qubit-cavity Rabi model can produce relatively large and nonmonotonic Bloch-Siegert shifts in the cavity frequency as the system is driven through a quantum-to-classical transition. Using a weak microwave probe tone, we demonstrate experimentally this effect by monitoring the resonance frequency of a microwave cavity coupled to a transmon and driven by a microwave field with varying power. In the weakly driven regime (quantum phase), the Bloch-Siegert shift appears as a small constant frequency shift, while for a strong drive (classical phase) it presents an oscillatory behavior as a function of the number of photons in the cavity. The experimental results are in agreement with numerical simulations based on the quasienergy spectrum.

Item Type:Articles
Additional Information:The authors are grateful for the financial support from the Academy of Finland (Projects No. 263457 and No. 135135), the Magnus Ehrnrooth Foundation, the Finnish Cultural Foundation, the Vilho, Yrjö, and Kalle Väisälä Foundation, FQXi, Centre of Quantum Engineering at Aalto University (Project QMET), and the Centres of Excellence LTQ (Project No. 250280), and COMP (Projects No. 251748 and No. 284621).
Glasgow Author(s) Enlighten ID:Danilin, Dr Sergey
Authors: Pietikäinen, I., Danilin, S., Kumar, K.S., Vepsäläinen, A., Golubev, D.S., Tuorila, J., and Paraoanu, G.S.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Journal Name:Physical Review B
Publisher:American Physical Society
ISSN (Online):1550-235X
Published Online:07 July 2017
Copyright Holders:Copyright © 2017 American Physical Society
First Published:First published in Physical Review B 96(2): 020501(R)
Publisher Policy:Reproduced in accordance with the publisher copyright policy
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