Resonance Fluorescence from an Artificial Atom in Squeezed Vacuum

Abstract

We present an experimental realization of resonance fluorescence in squeezed vacuum. We strongly couple microwave-frequency squeezed light to a superconducting artificial atom and detect the resulting fluorescence with high resolution enabled by a broadband traveling-wave parametric amplifier. We investigate the fluorescence spectra in the weak and strong driving regimes, observing up to 3.1 dB of reduction of the fluorescence linewidth below the ordinary vacuum level and a dramatic dependence of the Mollow triplet spectrum on the relative phase of the driving and squeezed vacuum fields. Our results are in excellent agreement with predictions for spectra produced by a two-level atom in squeezed vacuum [Phys. Rev. Lett. 58, 2539-2542], demonstrating that resonance fluorescence offers a resource-efficient means to characterize squeezing in cryogenic environments.

Magnetic Resonance with Squeezed Microwaves

“…Indeed, in steady state, squeezed radiation incident on a two-level system modifies its relaxation and coherence times as well as its average polarization, as predicted in Ref. [26] and observed in recent experiments with superconducting qubits [28,49]. Note that squeezing does not affect the damping rates of a harmonic oscillator, which explains its absence in the analysis of Sec.…”

“…Microwave squeezed states [20] can then provide a sizable noise reduction, thus improving measurement sensitivity for qubit state readout [21][22][23][24] and nanomechanical resonator motion detection [25]. They have also been investigated for their effect on the dynamics of quantum systems, such as two-level atoms [26][27][28] or mechanical oscillators [29]. Here, we propose and demonstrate a novel application of quantum squeezing at microwave frequencies to magnetic resonance spectroscopy for improving the detection sensitivity of a small ensemble of electronic spins.…”

Implementation of Traveling Odd Schrödinger Cat States in Circuit-QED

“…The proposed scheme has two main parts in Figure 1. The first part before a microwave BS shows how to generate the traveling SVS, which has been recently implemented in several world-leading groups [44][45][46][47][48]. The JTWPA is formed in a chain of Josephson junctions, capacitors, and inductors and the technique of resonant phase matching is used in a four-wave mixing process either to amplify an input signal or to generate an SVS.…”

“…We do not distinguish here between the JPA and JTWPA because both produce a traveling SVS even though they are quite different from each other on other characteristics. Using a traveling photon resource from JTWPA/JPA, many interesting experiments have been performed in circuit-QED beyond conventional experiments in quantum optics [46][47][48] and this technical development allows us to investigate traveling microwave qubits through transmission lines corresponding to a photonic QI processing in quantum optics [49]. For example, the most recent experiments have shown the detection schemes of a single microwave photon with excellent detection efficiency [50,51], which will be a key ingredient for traveling-microwave QI processing.…”

Waveguide quantum electrodynamics in squeezed vacuum

“…In contrast to the 3D case, squeezing in 1D is more experimentally feasible. Suppression of the radiative decay of atomic coherence and the linewidth of the resonance fluorescence have been experimentally demonstrated in a 1D microwave transmission line coupled to single artificial atom [26][27][28][29]. However, many-body interaction in a 1D waveguide-QED system coupled to squeezed vacuum has not yet been studied.…”