Search results for "non-Hermitian"
showing 7 items of 17 documents
Searching for exceptional points and inspecting non-contractivity of trace distance in (anti-) PT -symmetric systems
2022
Non-Hermitian systems with parity-time ($\mathcal{PT}$) symmetry and anti-$\mathcal{PT}$ symmetry give rise to exceptional points (EPs) with intriguing properties related to, e.g., chiral transport and enhanced sensitivity, due to the coalescence of eigenvectors. In this paper, we propose a powerful and easily computable tool, based on the Hilbert-Schmidt speed (HSS), which does not require the diagonalization of the evolved density matrix, to detect exactly the EPs and hence the critical behavior of the (anti-)$\mathcal{PT}\!-$symmetric systems, especially high-dimensional ones. Our theoretical predictions, made without the need for modification of the Hilbert space, which is performed by …
Exotic interactions mediated by a non-Hermitian photonic bath
2022
Photon-mediated interactions between quantum emitters in engineered photonic baths is an emerging area of quantum optics. At the same time, non-Hermitian (NH) physics is currently thriving, spurred by the exciting possibility to access new physics in systems ruled by non-trivial NH Hamiltonians - in particular photonic lattices - which can challenge longstanding tenets such as the Bloch theory of bands. Here, we combine these two fields and study the exotic interaction between emitters mediated by the photonic modes of a lossy photonic lattice described by a NH Hamiltonian. We show in a paradigmatic case study that structured losses in the field can seed exotic emission properties. Photons …
Non-Hermitian Hamiltonians in Quantum Physics
2016
This volume collects the selected contributions presented at or inspired by the15th International Workshop on Pseuso-Hermitian Hamiltonians in QuantumPhysics(PHHQP15), held in Palermo, Italy, from May 18 to 23, 2015. Thisworkshop was the 15th in the series of international meetings that was started in2003. These meetings were mainly attended by mathematicians and physicistsinterested in the study of non-Hermitian operators and Hamiltonians, and in theirphysical applications. About 80 mathematicians and physicists attended the 2015Workshop in Palermo.
Two-qubit entanglement generation through non-Hermitian Hamiltonians induced by repeated measurements on an ancilla
2020
In contrast to classical systems, actual implementation of non-Hermitian Hamiltonian dynamics for quantum systems is a challenge because the processes of energy gain and dissipation are based on the underlying Hermitian system&ndash
Gibbs states defined by biorthogonal sequences
2016
Motivated by the growing interest on PT-quantum mechanics, in this paper we discuss some facts on generalized Gibbs states and on their related KMS-like conditions. To achieve this, we first consider some useful connections between similar (Hamiltonian) operators and we propose some extended version of the Heisenberg algebraic dynamics, deducing some of their properties, useful for our purposes.
Non-Hermitian Physics and Master Equations
2022
A longstanding tool to characterize the evolution of open Markovian quantum systems is the GKSL (Gorini-Kossakowski-Sudarshan-Lindblad) master equation. However, in some cases, open quantum systems can be effectively described with non-Hermitian Hamiltonians, which have attracted great interest in the last twenty years due to a number of unconventional properties, such as the appearance of exceptional points. Here, we present a short review of these two different approaches aiming in particular to highlight their relation and illustrate different ways of connecting non-Hermitian Hamiltonian to a GKSL master equation for the full density matrix.
Non-Hermiticity in Quantum Physics
2022
The field of non-Hermitian Physics has attracted great attention over the last 23years, both from the in the physical and mathematical communities. From the physical point of view, non-Hermiticity was regarded as a phenomenological tool to describe open quantum systems. Besides this, the rising interest in this field comes especially from the possible exploitation of exceptional points for quantum technologies, and from the exotic topology arising in periodic non-Hermitian systems, connected to the so called non-Hermitian skin effect. From the mathematical point of view, the range of possible topics to investigate has been wide open, as dropping an hypothesis of a theory makes the mathemati…