Coherent Microwave Pulse Propagation in a Magnetic Two-Level System.

In many problems, the scattering amplitudes of a weak coherent pulse are almost equivalent to the ones of a single propagating photon. We thoroughly compare the scattering of (i) a short microwave coherent pulse from a rf generator and (ii) a vacuum-photon coherent superposition from the two-level emitter, both directed to a single two-level system---the probe. To do that, we use two superconducting qubits to implement emitter and probe, both strongly coupled to the same waveguide. However, with the use of a magnetic circulator we couple the field from the emitter to the probe without reverse backaction, thereby working with a cascaded atomic system implemented in a waveguide-QED setup. By measuring the dynamics of the scattered field, we find a certain discrepancy between two cases, confirmed by analytical and numerical study. Particularly, we find the optimal amplitude ${\mathrm{\ensuremath{\Omega}}}_{*}$ of classical pulse mimicking the superposition from the emitter, for which the difference becomes very small (but nonvanishing) and is almost unavailable to measure in practice.In many problems, the scattering amplitudes of a weak coherent pulse are almost equivalent to the ones of a single propagating photon. We thoroughly compare the scattering of (i) a short microwave coherent pulse from a rf generator and (ii) a vacuum-photon coherent superposition from the two-level emitter, both directed to a single two-level system---the probe. To do that, we use two superconducting qubits to implement emitter and probe, both strongly coupled to the same waveguide. However, with the use of a magnetic circulator we couple the field from the emitter to the probe without reverse backaction, thereby working with a cascaded atomic system implemented in a waveguide-QED setup. By measuring the dynamics of the scattered field, we find a certain discrepancy between two cases, confirmed by analytical and numerical study. Particularly, we find the optimal amplitude ${\mathrm{\ensuremath{\Omega}}}_{*}$ of classical pulse mimicking the superposition from the emitter, for which the difference becomes very small (but nonvanishing) and is almost unavailable to measure in practice.

Physical Review ASep 28, 20235 citations

The quantum and classical field scattered on a single two-level system

Sergei Gunin, Andrei Vladimirovich Vasenin, A. Yu. Dmitriev +3 more

In many problems, the scattering amplitudes of weak coherent pulse are almost equivalent to the ones of single propagating photon. We thoroughly compare the scattering of: (i) short microwave coherent pulse from rf generator and (ii) vacuum-photon coherent superposition from the two-level Emitter, both directed to a single two-level system (the Probe). To do that, we use two superconducting qubits to implement Emitter and Probe, both strongly coupled to the same waveguide. However, with the use of magnetic circulator we couple the field from Emitter to the Probe without reverse backaction, thereby working with a cascaded atomic system implemented in waveguide-QED setup. By measuring the dynamics of scattered field, we find a certain discrepancy between two cases, confirmed by analytical and numerical study. Particularly, we find the optimal amplitude $Ω_{*}$ of classical pulse mimicking the superposition from Emitter, for which the difference becomes very small (but non-vanishing), and is almost unavailable to measure in practice.In many problems, the scattering amplitudes of weak coherent pulse are almost equivalent to the ones of single propagating photon. We thoroughly compare the scattering of: (i) short microwave coherent pulse from rf generator and (ii) vacuum-photon coherent superposition from the two-level Emitter, both directed to a single two-level system (the Probe). To do that, we use two superconducting qubits to implement Emitter and Probe, both strongly coupled to the same waveguide. However, with the use of magnetic circulator we couple the field from Emitter to the Probe without reverse backaction, thereby working with a cascaded atomic system implemented in waveguide-QED setup. By measuring the dynamics of scattered field, we find a certain discrepancy between two cases, confirmed by analytical and numerical study. Particularly, we find the optimal amplitude $Ω_{*}$ of classical pulse mimicking the superposition from Emitter, for which the difference becomes very small (but non-vanishing), and is almost unavailable to measure in practice.

arXiv:2302.13762Feb 27, 20230 citations

Coherent pulse propagation through resonant media

Uwe van Bürck

Hyperfine InteractionsMar 1, 199973 citations

Gain-assisted superluminal microwave pulse propagation via four-wave mixing in superconducting phase quantum circuits

Zahra Amini Sabegh, Azar Vafafard, Mohammad Ali Maleki +1 more

We study the propagation and amplification of a microwave field in a four-level cascade quantum system which is realized in a superconducting phase quantum circuit. It is shown that by increasing the microwave pump tones feeding the system, the normal dispersion switches to the anomalous and the gain-assisted superluminal microwave propagation is obtained in this system. Moreover, it is demonstrated that the stimulated microwave field is generated via four-wave mixing without any inversion population in the energy levels of the system (amplification without inversion) and the group velocity of the generated pulse can be controlled by the external oscillating magnetic fluxes. We also show that in some special set of parameters, the absorption-free superluminal generated microwave propagation is obtained in superconducting phase quantum circuit system.We study the propagation and amplification of a microwave field in a four-level cascade quantum system which is realized in a superconducting phase quantum circuit. It is shown that by increasing the microwave pump tones feeding the system, the normal dispersion switches to the anomalous and the gain-assisted superluminal microwave propagation is obtained in this system. Moreover, it is demonstrated that the stimulated microwave field is generated via four-wave mixing without any inversion population in the energy levels of the system (amplification without inversion) and the group velocity of the generated pulse can be controlled by the external oscillating magnetic fluxes. We also show that in some special set of parameters, the absorption-free superluminal generated microwave propagation is obtained in superconducting phase quantum circuit system.

arXiv:1502.06350Feb 23, 20150 citations

Ω_{*}

of classical pulse mimicking the superposition from Emitter, for which the difference becomes very small (but non-vanishing), and is almost unavailable to measure in practice.