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Classical open systems with balanced gain and loss, i.e. parity-time ($\mathcal{PT}$) symmetric systems, have attracted tremendous attention over the past decade. Their exotic properties arise from exceptional point (EP) degeneracies of…

Quantum Physics · Physics 2021-02-17 Zachary A. Cochran , Avadh Saxena , Yogesh N. Joglekar

The Hermiticity axiom of quantum mechanics guarantees that the energy spectrum is real and the time evolution is unitary (probability-preserving). Nevertheless, non-Hermitian but $\mathcal{PT}$-symmetric Hamiltonians may also have real…

Quantum Physics · Physics 2018-06-06 Fernando Quijandría , Uta Naether , Sahin K. Özdemir , Franco Nori , David Zueco

While parity-time (PT)-symmetric systems can exhibit real spectra in the exact PT-symmetry regime, the PT-symmetry is actually not a necessary condition for the real spectra. Here we show that non-PT-symmetric photonic crystals carrying…

Optics · Physics 2019-12-24 Xiaohan Cui , Kun Ding , Jianwen Dong , C. T. Chan

Since the realization of quantum systems described by non-Hermitian Hamiltonians with parity-time (PT) symmetry, interest in non-Hermitian, quantum many-body models has steadily grown. Most studies to-date map to traditional quantum spin…

Quantum Physics · Physics 2023-12-07 Jacob Muldoon , Yogesh N. Joglekar

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

Non-Hermiticity has recently emerged as a rapidly developing field due to its exotic characteristics related to open systems, where the dissipation plays a critical role. In the presence of balanced energy gain and loss with environment,…

Optics · Physics 2024-04-10 Chang Li , Ruisheng Yang , Xinchao Huang , Quanhong Fu , Yuancheng Fan , Fuli Zhang

Non-Hermitian systems satisfying parity-time (PT) symmetry have aroused considerable interest owing to their exotic features. Anti-PT symmetry is an important counterpart of the PT symmetry, and has been studied in various classical…

Quantum Physics · Physics 2024-06-21 Ji Bian , Pengfei Lu , Teng Liu , Hao Wu , Xinxin Rao , Kunxu Wang , Qifeng Lao , Yang Liu , Feng Zhu , Le Luo

We study the properties of a parity- and time-reversal- (PT) symmetric tight-binding chain of size N with position-dependent hopping amplitude. In contrast to the fragile PT-symmetric phase of a chain with constant hopping and imaginary…

Quantum Physics · Physics 2011-05-06 Yogesh N. Joglekar , Avadh Saxena

In addition to the implementation of parity-time ($\mathcal{PT}$)-symmetric optical systems by carefully and actively controlling the gain and loss, we show that a $2\times 2$ $\mathcal{PT}$-symmetric Hamiltonian has a unitarily equivalent…

Optics · Physics 2017-01-12 Yi-Chan Lee , Jibing Liu , You-Lin Chuang , Min-Hsiu Hsieh , Ray-Kuang Lee

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

Although people have already artificially formed parity--time ($\mathcal{PT}$) symmetry with gain and loss in a balanced manner, it is still a defect that the gain is restricted to semi--classical but not full quantum. Here we propose and…

Quantum Physics · Physics 2017-02-22 Wenlin Li , Chong Li , Heshan Song

The Parity-Time ($\mathcal{PT}$) symmetric potentials are derived by non-Hermitian supersymmetric quantum mechanics for square well and barrier. These $\mathcal{PT}$-supersymmetric square well and barrier. The partners have complex…

Quantum Physics · Physics 2020-01-28 Taha Koohrokhi

In this article, we have introduced a $\mathcal{PT}$ symmetric non-Hermitian Hamiltonian model which is given as $\hat{\mathcal{H}}=\omega (\hat{b}^{\dag}\hat{b}+1/2)+ \alpha (\hat{b}^{2}-(\hat{b}^{\dag})^{2})$ where $\omega$ and $\alpha$…

Mathematical Physics · Physics 2015-06-12 O. Yesiltas

Update: A time-independent $n\times n$ PT-symmetric (and symmetric) Hamiltonian is diagonalizable since it has all distinct real eigenvalues and the resulting diagonal matrix is a real symmetric matrix. The diagonalization results an…

Quantum Physics · Physics 2014-05-20 Sungwook Lee , Lawrence R. Mead

Non-Hermitian optical systems with parity-time (PT) symmetry have recently revealed many intriguing prospects that outperform conservative structures. The prevous works are mostly rooted in complex arrangements with controlled gain-loss…

Optics · Physics 2019-11-13 Yue Jiang , Yefeng Mei , Ying Zuo , Yanhua Zhai , Jensen Li , Jianming Wen , Shengwang Du

Parity-time-symmetric ($\mathcal{PT}$-symmetric) optical waveguide couplers have become a key component for integrated optics. They offer new possibilities for fast, ultracompact, configurable, all-optical signal processing. Here, we study…

Optics · Physics 2015-09-14 Wiktor Walasik , Natalia M. Litchinitser

Parity-time (PT) symmetry is a fundamental notion in quantum field theories. It has opened a new paradigm for non-Hermitian Hamiltonians ranging from quantum mechanics, electronics, to optics. In the realm of optics, optical loss is…

Optics · Physics 2014-10-21 Liang Feng , Zi Jing Wong , Renmin Ma , Yuan Wang , Xiang Zhang

We consider the role of non-triviality resulting from a non-Hermitian Hamiltonian that conserves twofold PT-symmetry assembled by interconnections between a PT-symmetric lattice and its time reversal partner. Twofold PT-symmetry in the…

Mesoscale and Nanoscale Physics · Physics 2020-08-05 Jung-Wan Ryu , Nojoon Myoung , Sungjong Woo , Ara Go , Sang-Jun Choi , Hee Chul Park

Conserved quantities such as energy or the electric charge of a closed system, or the Runge-Lenz vector in Kepler dynamics are determined by its global, local, or accidental symmetries. They were instrumental to advances such as the…

The occurrence of parity-time reversal ($\mathcal{PT}$) symmetry breaking is discussed in a non-Hermitian spin chain. The Hermiticity of the model is broken by the presence of an alternating, imaginary, transverse magnetic field. A full…

Quantum Physics · Physics 2010-08-25 Gian Luca Giorgi