35 research outputs found
Evolution of coherent waves driving a single artificial atom
An electromagnetic wave propagating through a waveguide with a strongly
coupled superconducting artificial two-level atom exhibits an evolving
superposition with the atom. The Rabi oscillations in the atom result from a
single excitation-relaxation, corresponding to photon absorption and stimulated
emission from/to the field. In this study, we investigate the time-dependent
behavior of the transmitted field and extract its spectra. The scattered fields
are described using input-output theory. We demonstrate that the time evolution
of the propagating fields, due to interaction, encapsulates all information
about the atom. Additionally, we deduce the dynamics of the incoherent
radiation component from the measured first-order correlation function of the
field.Comment: Main text: 6 pages, 4 figures; Supplemental Material: 4 pages, 1
figure; updated commen
Demonstration of a parity-time symmetry breaking phase transition using superconducting and trapped-ion qutrits
Scalable quantum computers hold the promise to solve hard computational
problems, such as prime factorization, combinatorial optimization, simulation
of many-body physics, and quantum chemistry. While being key to understanding
many real-world phenomena, simulation of non-conservative quantum dynamics
presents a challenge for unitary quantum computation. In this work, we focus on
simulating non-unitary parity-time symmetric systems, which exhibit a
distinctive symmetry-breaking phase transition as well as other unique features
that have no counterpart in closed systems. We show that a qutrit, a
three-level quantum system, is capable of realizing this non-equilibrium phase
transition. By using two physical platforms - an array of trapped ions and a
superconducting transmon - and by controlling their three energy levels in a
digital manner, we experimentally simulate the parity-time symmetry-breaking
phase transition. Our results indicate the potential advantage of multi-level
(qudit) processors in simulating physical effects, where additional accessible
levels can play the role of a controlled environment.Comment: 14 pages, 9 figure