It is generally assumed that a Hamiltonian for a physically acceptable quantum system (one
that has a positive-definite spectrum and obeys the requirement of unitarity) must be …

Quantum technology has made tremendous strides over the past two decades with
remarkable advances in materials engineering, circuit design, and dynamic operation. In …

Out of equilibrium, a lack of reciprocity is the rule rather than the exception. Non-reciprocity
occurs, for instance, in active matter,,,,–, non-equilibrium systems,–, networks of neurons …

Solids built out of active components can exhibit nonreciprocal elastic coefficients that give
rise to non-Hermitian wave phenomena. Here, we investigate non-Hermitian effects present …

Dissipation in mechanics, optics, acoustics, and electronic circuits is nowadays recognized
to be not always detrimental but can be exploited to achieve non-Hermitian topological …

Non-Hermitian Hamiltonians provide an alternative perspective on the dynamics of quantum
and classical systems coupled non-conservatively to an environment. Once primarily an …

Antiferromagnetic materials have recently gained renewed interest due to their possible use
in spintronics technologies, where spin transport is the foundation of their functionalities. In …

We theoretically investigate the dynamics of two spin qubits interacting with a magnetic
medium. A systematic formal framework for this qubit-magnet hybrid system is developed in …

We provide an experimental framework where periodically driven PT-symmetric systems can
be investigated. The setup, consisting of two ultra high frequency oscillators coupled by a …

Non-Hermitian Hamiltonians may still have real eigenvalues, provided that a combined
parity-time (ƤƮ) symmetry exists. The prospect of ƤƮ symmetry has been explored in …