47 research outputs found
Singly-excited resonant open quantum system Tavis-Cummings model with quantum circuit mapping
Tavis-Cummings (TC) cavity quantum electrodynamical effects, describing the
interaction of atoms with an optical resonator, are at the core of atomic,
optical and solid state physics. The full numerical simulation of TC dynamics
scales exponentially with the number of atoms. By restricting the open quantum
system to a single excitation, typical of experimental realizations in quantum
optics, we analytically solve the TC model with an arbitrary number of atoms
with linear complexity. This solution allows us to devise the Quantum Mapping
Algorithm of Resonator Interaction with Atoms (Q-MARINA), an intuitive TC
mapping to a quantum circuit with linear space and time scaling, whose
qubits represent atoms and a lossy cavity, while the dynamics is encoded
through entangling gates. Finally, we benchmark the robustness of the
algorithm on a quantum simulator and superconducting quantum processors against
the quantum master equation solution on a classical computer.Comment: 15 pages, 4 figure
Efficient quantum algorithms for testing symmetries of open quantum systems
Symmetry is an important and unifying notion in many areas of physics. In
quantum mechanics, it is possible to eliminate degrees of freedom from a system
by leveraging symmetry to identify the possible physical transitions. This
allows us to simplify calculations and characterize potentially complicated
dynamics of the system with relative ease. Previous works have focused on
devising quantum algorithms to ascertain symmetries by means of fidelity-based
symmetry measures. In our present work, we develop alternative symmetry testing
quantum algorithms that are efficiently implementable on quantum computers. Our
approach estimates asymmetry measures based on the Hilbert--Schmidt distance,
which is significantly easier, in a computational sense, than using fidelity as
a metric. The method is derived to measure symmetries of states, channels,
Lindbladians, and measurements. We apply this method to a number of scenarios
involving open quantum systems, including the amplitude damping channel and a
spin chain, and we test for symmetries within and outside the finite symmetry
group of the Hamiltonian and Lindblad operators.Comment: 47 pages, 11 figures, submission to the second journal special issue
dedicated to the memory of G\"oran Lindbla
Triangular Cross-Section Beam Splitters in Silicon Carbide for Quantum Information Processing
Triangular cross-section color center photonics in silicon carbide is a
leading candidate for scalable implementation of quantum hardware. Within this
geometry, we model low-loss beam splitters for applications in key quantum
optical operations such as entanglement and single-photon interferometry. We
consider triangular cross-section single-mode waveguides for the design of a
directional coupler. We optimize parameters for a 50:50 beam splitter. Finally,
we test the experimental feasibility of the designs by fabricating triangular
waveguides in an ion beam etching process and identify suitable designs for
short-term implementation