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We consider information spreading measures in randomly initialized variational quantum circuits and introduce entanglement diagnostics for efficient variational quantum/classical computations. We establish a robust connection between…

Quantum Physics · Physics 2022-07-27 Joonho Kim , Yaron Oz

Important properties of a quantum system are not directly measurable, but they can be disclosed by how fast the system changes under controlled perturbations. In particular, asymmetry and entanglement can be verified by reconstructing the…

The construction of two-qubit gates appropriate for universal quantum computation is of enormous importance to quantum information processing. Building such gates is dependent on accurate knowledge of the interaction dynamics between two…

Quantum Physics · Physics 2009-11-11 Simon J. Devitt , Jared H. Cole , Lloyd C. L. Hollenberg

Entanglement is the powerful and enigmatic resource central to quantum information processing, which promises capabilities in computing, simulation, secure communication, and metrology beyond what is possible for classical devices. Exactly…

The process of measuring a two-level quantum system was examined by applying Hamiltonian formalism. For the measurement of an observable that does not commute with the system Hamiltonian, a non-trivial relationship among the strength of…

Quantum Physics · Physics 2011-05-24 Takayuki Miyadera

Entanglement is the key resource for quantum technologies and is at the root of exciting many-body phenomena. However, quantifying the entanglement between two parts of a real-world quantum system is challenging when it interacts with its…

Quantum Physics · Physics 2023-03-22 Christian Carisch , Oded Zilberberg

Entanglement is a fundamental feature of quantum mechanics and holds great promise for enhancing metrology and communications. Much of the focus of quantum metrology so far has been on generating highly entangled quantum states that offer…

Quantum entanglement is known as a unique quantum feature that cannot be obtained by classical physics. Over the last several decades, however, such an understanding on quantum entanglement might have confined us in a limited world of weird…

Quantum Physics · Physics 2023-08-01 B. S. Ham

In this paper we consider the problem of tracking the state of a quantum system via a continuous measurement. If the system Hamiltonian is known precisely, this merely requires integrating the appropriate stochastic master equation.…

Quantum Physics · Physics 2011-11-29 Jason F. Ralph , Kurt Jacobs , Charles D. Hill

We upper- and lower-bound the optimal precision with which one can estimate an unknown Hamiltonian parameter via measurements of Gibbs thermal states with a known temperature. The bounds depend on the uncertainty in the Hamiltonian term…

We explore the possibility of the controlled manipulation of the entanglement of two qubits with an external apparatus, the Rabi Hamiltonian. The novel results show that the initially entangled two qubits could have very high probability to…

Quantum Physics · Physics 2013-10-01 Guihua Tian , Shuquan Zhong

We examine the physical manifestations of exceptional points and passage times in a two-level system which is subjected to quantum measurements and which admits a non-Hermitian description. Using an effective Hamiltonian acting in the…

Quantum Physics · Physics 2015-06-12 A. Thilagam

The problem of diagonalization of Hamiltonians of N-dimensional boson systems by means of time-dependent canonical transformations (CT) is considered, the case of quadratic Hamiltonians being treated in greater detail. The unitary generator…

Quantum Physics · Physics 2007-05-23 D. A. Trifonov

Entanglement is a distinguishing feature of quantum many-body systems, and uncovering the entanglement structure for large particle numbers in quantum simulation experiments is a fundamental challenge in quantum information science. Here we…

The entanglement Hamiltonian (EH) provides the most comprehensive characterization of bipartite entanglement in many-body quantum systems. Ground states of local Hamiltonians inherit this locality, resulting in EHs that are dominated by…

Quantum Physics · Physics 2025-04-07 Federico Rottoli , Colin Rylands , Pasquale Calabrese

Consider two quantum systems A and B interacting according to a product Hamiltonian H = H_A x H_B. We show that any two such Hamiltonians can be used to simulate each other reversibly (i.e., without efficiency losses) with the help of local…

Quantum Physics · Physics 2007-05-23 Andrew M. Childs , Debbie W. Leung , Guifre Vidal

It is natural to measure the observables from the Hamiltonian-based quantum dynamics, and its inverse process that Hamiltonians are estimated from the measured data also is a vital topic. In this work, we propose a recurrent neural network…

Quantum Physics · Physics 2021-06-30 Liangyu Che , Chao Wei , Yulei Huang , Dafa Zhao , Shunzhong Xue , Xinfang Nie , Jun Li , Dawei Lu , Tao Xin

The Heisenberg limit is the superior precision available by entanglement sensors. However, entanglementis fragile against dephasing, and there is no known quantum metrology protocol that can achieve Heisenberg limited sensitivity with the…

Quantum Physics · Physics 2018-09-05 Yuichiro Matsuzaki , Shiro Saito , William J. Munro

Recently, the entanglement dynamics of two harmonic oscillators initially prepared in a separable-coherent state was demonstrated to offer a pathway for prime number identification. This article presents a generalized approach and outlines…

Quantum Physics · Physics 2024-08-09 Victor F. dos Santos , Jonas Maziero

Identifying the nature of interactions in a quantum system is essential in understanding any physical phenomena. Acquiring information on the Hamiltonian can be a tough challenge in many-body systems because it generally requires access to…

Quantum Physics · Physics 2009-10-09 Daniel Burgarth , Koji Maruyama