Persistent current induced by quantum light

Abstract

It is demonstrated that the strong coupling of an electron gas to photons in systems with broken time-reversal symmetry results in bound electron-photon states which cannot be backscattered elastically. As a consequence, the electron gas can flow without dissipation. This quantum macroscopic phenomenon leads to the unconventional superconductivity which is analyzed theoretically for a two-dimensional electron system in a semiconductor quantum well exposed to an in-plane magnetic field.Comment: 6 pages, 2 figures; published versio

Resonance fluorescence from an asymmetric quantum dot dressed by a bichromatic electromagnetic field

“…is the positive(negative)-frequency part of the polarization operator written in the basis of dressed states (13)- (14). Applying the quantum regression theorem [2] and taking into account Eqs.…”

“…Therefore, the system "electron + strong field" is conventionally considered as a composite electron-field object which was called "electron dressed by field" (dressed electron) [1,2]. The field-induced modification of physical properties of dressed electrons was studied in both atomic systems [1][2][3] and various condensed-matter structures, including bulk semiconductors [4][5][6], graphene [7][8][9][10][11], quantum wells [12][13][14][15][16][17], quantum rings [18][19][20][21], quantum dots [22][23][24][25][26][27][28][29][30][31][32], etc. Among these structures, quantum dots (QDs) -semiconductor 3D structures of nanometer scale, which are referred to as "artificial atoms" -seem to be most interesting for optical studies since they are basic elements of modern nanophotonics [33,34].…”

Semiconductor cavity QED: Band gap induced by vacuum fluctuations

“…In order to verify the developed diagrammatic approach, let us apply it to a semiconductor system excited by a strong laser-generated electromagnetic field. This system can be described using the methods of classical electrodynamics, and the theory of the gap opening induced by a laser has been elaborated in details [6,7,9,10]. Therefore, it is instructive to compare this well-known theory with results obtained from the discussed diagrammatic approach in the limit of large photon occupation numbers.…”

“…Particularly, the dynamic Stark effect opens stationary bandgaps in semiconductor systems, which take place in resonant points of the Brillouin zone satisfying the condition where the photon energy is equal to the energy interval between electron bands of the semiconductor. This gap can manifest itself in various physical effects [8][9][10]. …”

“…The investigation of the regime of strong light-matter coupling, where the interaction between photons and material excitations can not be treated perturbatively, is of special interest. One of the fundamental phenomena in this domain is the dynamic (AC) Stark effect [1] associated with the stationary energy shift of electron energy levels under the influence of an electromagnetic wave and taking place in both atomic systems and solids [2][3][4][5][6][7][8][9][10]. Particularly, the dynamic Stark effect opens stationary bandgaps in semiconductor systems, which take place in resonant points of the Brillouin zone satisfying the condition where the photon energy is equal to the energy interval between electron bands of the semiconductor.…”