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Open systems with gain, loss, or both, described by non-Hermitian Hamiltonians, have been a research frontier for the past decade. In particular, such Hamiltonians which possess parity-time ($\mathcal{PT}$) symmetry feature dynamically…

Quantum Physics · Physics 2021-01-01 Andrew K. Harter , Yogesh N. Joglekar

Non-Hermitian systems with parity-time ($\mathcal{PT}$) symmetry give rise to exceptional points (EPs) with exceptional properties that arise due to the coalescence of eigenvectors. Such systems have been extensively explored in the…

Recently, the study of non-Hermitian physics has attracted considerable attention. The modified bulk-boundary correspondence has been proposed to understand topological edge states in non-Hermitian static systems. Here we report a new…

Optics · Physics 2019-06-18 Bo Wang , Tian Chen , Xiangdong Zhang

In this study, we investigate qubit dynamics under PT and Anti-PT-symmetric non-Hermitian Hamiltonians, focusing on phase evolution, decoherence, quantum speed limits (QSL), and R\'enyi entanglement entropies. Using similarity…

Quantum Physics · Physics 2025-08-11 Amir Ahmadi , Roozbeh H. Asgari , Javad T. Firouzjaee

Parity-time (PT) symmetric non-Hermitian Hamiltonians bring about many novel features and interesting applications such as quantum gates faster than those in Hermitian systems, and topological state transfer. The performance of evolutions…

Quantum Physics · Physics 2022-07-20 Ji Bian , Kunxu Wang , Pengfei Lu , Xinxin Rao , Hao Wu , Qifeng Lao , Teng Liu , Yang Liu , Feng Zhu , Le Luo

We demonstrate that quantum fluctuations can cause, under certain conditions, the dynamical instability of pure states that can result in their evolution into mixed states. It is shown that the degree and type of such an instability are…

Quantum Physics · Physics 2015-11-19 Konstantin G. Zloshchastiev

Quantum computing's potential for exponential speedup is fundamentally limited by decoherence, a phenomenon arising from environmental interactions. Non-Hermitian quantum mechanics, particularly $PT$-symmetric systems, offers a novel…

Quantum Physics · Physics 2025-11-25 Duttatreya , Ipsika Mohanty , Sanjib Dey

We investigate a two-level spin system based anti-parity-time (anti-$\mathcal{PT}$)-symmetric qubit and study its decoherence as well as entanglement entropy properties. We compare our findings with that of the corresponding…

Quantum Physics · Physics 2020-08-12 Julia Cen , Avadh Saxena

We experimentally demonstrate an unambiguous quantum state discrimination of two qubit states under a non-Hermitian Hamiltonian with parity-time-reversal ($\mathcal{PT}$) symmetry in a single trapped $^{40}$Ca$^+$ ion. We show that any two…

Quantum Physics · Physics 2025-03-03 Chenhao Zhu , Tingting Shi , Liangyu Ding , Zhiyue Zheng , Xiang Zhang , Wei Zhang

For a subclass of a general $\mathcal{PT}-$symmetric Hamiltonian obeying anti-commutation relation with its conjugate, a Hermitian basis is found that spans the bi-orthonormal energy eigenvectors. Using the modified projectors constructed…

Quantum Physics · Physics 2025-12-04 Baibhab Bose , Devvrat Tiwari , Subhashish Banerjee

The dynamics of an open quantum system with balanced gain and loss is not described by a PT-symmetric Hamiltonian but rather by Lindblad operators. Nevertheless the phenomenon of PT-symmetry breaking and the impact of exceptional points can…

Quantum Physics · Physics 2021-05-21 Dorje C. Brody

Spontaneous symmetry-breaking in phase transitions occurs when the system Hamiltonian is symmetric under a certain transformation, but the equilibrium states observed in nature are not. Here, we prove that when a discrete symmetry is…

Quantum Physics · Physics 2024-12-13 Ángel L. Corps , Armando Relaño

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-environment…

Quantum Physics · Physics 2020-10-23 R. Grimaudo , A. Messina , A. Sergi , N. V. Vitanov , S. N. Filippov

We find a new effect for the behaviour of Von Neumann entropy. For this we derive the framework for describing Von Neumann entropy in non-Hermitian quantum systems and then apply it to a simple interacting PT symmetric bosonic system. We…

Quantum Physics · Physics 2019-08-01 Andreas Fring , Thomas Frith

Recently, open systems with balanced, spatially separated loss and gain have been realized and studied using non-Hermitian Hamiltonians that are invariant under the combined parity and time-reversal ($\mathcal{PT}$) operations. Here, we…

Quantum Physics · Physics 2013-09-10 Harsha Vemuri , Yogesh N. Joglekar

Entanglement is one of the key feature of quantum world that has no classical counterpart. This arises due to the linear superposition principle and the tensor product structure of the Hilbert space when we deal with multiparticle systems.…

Quantum Physics · Physics 2011-09-14 Arun Kumar Pati

Quantum physics can be extended into the complex domain by considering non-Hermitian Hamiltonians that are $\mathcal{PT}$-symmetric. These exhibit exceptional points (EPs) where the eigenspectrum changes from purely real to purely imaginary…

Quantum Physics · Physics 2025-06-23 Jia-Jia Wang , Yu-Hong He , Chang-Geng Liao , Rong-Xin Chen , Jacob A. Dunningham

We propose random non-Hermitian Hamiltonians to model the generic stochastic nonlinear dynamics of a quantum state in Hilbert space. Our approach features an underlying linearity in the dynamical equations, ensuring the applicability of…

Quantum Physics · Physics 2025-07-31 Pei Wang

Through the study of the Rep($D_8$) non-invertible symmetry, we show how non-invertible symmetries manifest in dynamics. By considering the effect of symmetry preserving disorder, the non-invertible symmetry is shown to give rise to…

Strongly Correlated Electrons · Physics 2025-08-21 Yabo Li , Aditi Mitra

Non-Hermitian two-site ``dimers'' serve as minimal models in which to explore the interplay of gain and loss in dynamical systems. In this paper, we experimentally and theoretically investigate the dynamics of non-Hermitian dimer models…

Mesoscale and Nanoscale Physics · Physics 2023-08-02 Enrico Martello , Yaashnaa Singhal , Bryce Gadway , Tomoki Ozawa , Hannah M. Price