Relaxation, decoherence, and steady-state population inversion in qubits doubly dressed by microwave and radiofrequency fields

Abstract

The coherent dynamics of relaxing spin qubits driven by a classical bichromatic field comprising a strong resonant component and a weaker component with a frequency close to the strong-field Rabi frequency is studied. The double dressing by the bichromatic field modifies dephasing and dissipation processes. We demonstrate that detuning of the weakerfield frequency from the strong-field Rabi frequency prolongs the decay of Rabi oscillations between some doubly dressed states. The sensitivity of Rabi oscillations to the modified detuning-dependent relaxation is illustrated for nitrogen-vacancy qubits in diamond. We discuss a steady-state population inversion of the doubly dressed-state levels.

Rabi-resonant behavior of periodically driven correlated fermion systems

“…The perturbative Hamiltonian indicates that driving couples Hubbard bands like a classical field acts on a two-level atom. The latter system is described by the Rabi model [32,33], which can support resonant rapid energy absorption at series of critical frequencies of the drive [34][35][36][37][38] in the virtually quantitative agreement with those revealed in the Fermi-Hubbard model [29]. The indicated correspondence to a two-level atom driven by a field is further supported by the equivalence between dynamics of twosite Fermi-Hubbard and Rabi models.…”

“…With the help of the static perturbation approach we argue that Hubbard bands are coupled by driving in a similar manner as a classical field with transverse and longitudinal components acts on a two-level atom. The latter scenario, formally described by the quantum optical Rabi model, though significantly simpler than the Fermi-Hubbard system, supports resonant rapid energy absorption [34][35][36][37][38] at virtually the same frequencies of a drive. Our interpretation is further supported by equivalency between dynamics of driven two-site half-filled Hubbard and Rabi models.…”

“…in the absence of longitudinal driving (Ω z = 0) [32,33], leads to the resonant population of the high energy level when field frequency is synchronized with the level separation ω = Ω 0 . Additionally, for strong drivings Ω x /Ω 0 1, multiphoton resonances can be seen at ω (n) ≈ Ω 0 /(2n + 1), for positive integer n. In turn, when Ω z = 0 [34][35][36][37][38] resonances can appear at all integer submultiples of level separation, ω n ≈ Ω 0 /n, n ∈ Z, even for weak transverse drivings. This is due to multiphoton processes involving quanta from the longitudinal part of the driving (for details see Supplemental Material [50]).…”

Emission Spectrum of a Qubit under Its Deep Strong Driving in the High-Frequency Dispersive Regime

“…The description of this method and its applications to studies of the dynamics of two-level systems under mono-and bichromatic driving are presented in Refs. [27,33,34]. In the high-frequency limit, /1  , and in the first order of non-secular perturbation theory the Hamiltonian H is replaced by its effective counterpart:…”

Signal amplification in a qubit-resonator system

“…The ability of stimulated emission and lasing in superconductive devices has been actively studied during the last several years both theoretically [8][9][10][11][12] and experimentally [13][14][15]. The work is underway on using these phenomena as basis for a quantum amplifier of signals near the quantum limit.…”