Title: Vacuum Bloch–Siegert shift in Landau polaritons with ultra-high cooperativity

Abstract

Here, a two-level system resonantly interacting with an a.c. magnetic or electric field constitutes the physical basis of diverse phenomena and technologies. However, Schrödinger’s equation for this seemingly simple system can be solved exactly only under the rotating-wave approximation, which neglects the counter-rotating field component. When the a.c. field is sufficiently strong, this approximation fails, leading to a resonance-frequency shift known as the Bloch–Siegert shift. Here, we report the vacuum Bloch–Siegert shift, which is induced by the ultra-strong coupling of matter with the counter-rotating component of the vacuum fluctuation field in a cavity. Specifically, an ultra-high-mobility two-dimensional electron gas inside a high-Q terahertz cavity in a quantizing magnetic field revealed ultra-narrow Landau polaritons, which exhibited a vacuum Bloch–Siegert shift up to 40 GHz. This shift, clearly distinguishable from the photon-field self-interaction effect, represents a unique manifestation of a strong-field phenomenon without a strong field.

Authors:

Li, Xinwei ^[1]; Bamba, Motoaki  ^[2];

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Zhang, Qi  ^[3];

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Fallahi, Saeed ^[4]; Gardner, Geoff C. ^[4]; Gao, Weilu  ^[1];

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Lou, Minhan ^[1]; Yoshioka, Katsumasa ^[5]; Manfra, Michael J. ^[4]; Kono, Junichiro  ^[1]

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+ Show Author Affiliations

1. Rice Univ., Houston, TX (United States)
2. Osaka Univ., Osaka (Japan); PRESTO, Japan Science and Technology Agency, Saitama (Japan)
3. Argonne National Lab. (ANL), Lemont, IL (United States)
4. Purdue Univ., West Lafayette, IN (United States)
5. Yokohama National Univ., Yokohama (Japan)

Publication Date:

2018-04-16

Research Org.:

Argonne National Lab. (ANL), Argonne, IL (United States)

Sponsoring Org.:

National Science Foundation (NSF); US Army Research Office (ARO); USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1489492

Grant/Contract Number:  

AC02-06CH11357

Resource Type:

Accepted Manuscript

Journal Name:

Nature Photonics

Additional Journal Information:

Journal Volume: 12; Journal Issue: 6; Journal ID: ISSN 1749-4885

Publisher:

Nature Publishing Group

Country of Publication:

United States

Language:

English

Subject:

42 ENGINEERING