Numerical study of Wigner negativity in one-dimensional steady-state resonance fluorescence

Abstract

In a numerical study, we investigate the steady-state generation of nonclassical states of light from a coherently driven two-level atom in a one-dimensional waveguide. Specifically, we look for states with a negative Wigner function, since such nonclassical states are a resource for quantum information processing applications, including quantum computing. We find that a waveguide terminated by a mirror at the position of the atom can provide Wigner-negative states, while an infinite waveguide yields strictly positive Wigner functions. Moreover, our investigation reveals a connection between the purity of a quantum state and its Wigner negativity. We also analyze the effects of decoherence on the negativity of a state.

Quasi-probability information in a coupled two-qubit system interacting non-linearly with a coherent cavity under intrinsic decoherence

“…Recently, the non-classicality and the quantum coherence were used to realize quantum computations 53 , 54 , quantum tomography 55 , quantum interference 56 as well as to implement large cat states in finite-temperature reservoir 57 .…”

Interaction signatures and non-Gaussian photon states from a strongly driven atomic ensemble coupled to a nanophotonic waveguide

“…when Π t (X α ) has not yet converged to a delta-distribution. Integration-time dependent Wigner functions were also observed in [42], where the photo current was calculated from a stochastic master equation. The approach we pursue here allows us to directly access the rate function and thus the distribution function of the photo current without the need to perform Monte Carlo averages.…”

“…Signatures of non-classicality can be observed already at intermediate driving strength. To characterise the state of the light emitted from the nanofiber mode, we perform an analysis of the time-integrated photo current observed via homodyne detection X α [42]. For long times, i.e.…”

“…4e). For Ω γ, the nonlinear response of the twolevel systems leads to negativity in the WD and hence non-gaussianity of the emitted light [42,48], which grows with the number of atoms N (third row in Fig. 4e).…”

“…We analyze the quantum state of the light emitted into the reservoir (here the right-propagating guided mode) by studying the timeintegrated quadratures. A similar approach was pursued in [42] to analyze resonance fluorescence in the stationary state. The challenge is that the light field at the output is not confined to a cavity with a well-defined stationary quantum state but is rather characterized by continuousmode field operators B(t).…”