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We present a mean-photon-number dependent variational method, which works well in whole coupling regime if the photon energy is dominant over the spin-flipping, to evaluate the properties of the Rabi model for both the ground state and the…

Quantum Physics · Physics 2017-02-24 Maoxin Liu , Zu-Jian Ying , Jun-Hong An , Hong-Gang Luo

A sufficient condition for a quantum state of a system of spin-1/2 particles (spin-1/2s) to admit a local hidden variable (LHV) description i.e. to be classical is the separability of the density matrix characterizing its state, but not all…

Quantum Physics · Physics 2015-06-23 R. R. Puri

Creating macroscopic spatial superposition states is crucial for investigating matter-wave interferometry and advancing quantum sensor technology. Currently, two potential methods exist to achieve this objective. The first involves using…

Quantum Physics · Physics 2025-04-14 Run Zhou , Qian Xiang , Anupam Mazumdar

Tensor networks capture large classes of ground states of phases of quantum matter faithfully and efficiently. Their manipulation and contraction has remained a challenge over the years, however. For most of the history, ground state…

Strongly Correlated Electrons · Physics 2024-09-11 Jan Naumann , Erik Lennart Weerda , Matteo Rizzi , Jens Eisert , Philipp Schmoll

A method for generating a mesoscopic superposition state of the collective spin variable of a gas of atoms is proposed. The state consists of a superposition of the atomic spins pointing in two slightly different directions. It is obtained…

Quantum Physics · Physics 2009-11-10 S. Massar , E. S. Polzik

Variational wave function ansatze are an invaluable tool to study the properties of strongly correlated systems. We propose such a wave function, based on the theory of auxiliary fields and combining aspects of auxiliary-field quantum Monte…

Strongly Correlated Electrons · Physics 2024-03-13 Ryan Levy , Miguel A. Morales , Shiwei Zhang

Under the spin-position decoupling approximation, a vector with a phase in 3D orientation space endowed with geometric algebra, substitutes the vector-matrix spin model built on the Pauli spin operator. The standard quantum operator-state…

Quantum Physics · Physics 2022-12-20 Sokol Andoni

Quantum state tomography is an integral part of quantum computation and offers the starting point for the validation of various quantum devices. One of the central tasks in the field of state tomography is to reconstruct with high fidelity,…

Quantum Physics · Physics 2022-12-21 Rishabh Gupta , Manas Sajjan , Raphael D. Levine , Sabre Kais

We show that a quantum state may be represented as the sum of a joint probability and a complex quantum modification term. The joint probability and the modification term can both be observed in successive projective measurements. The…

Quantum Physics · Physics 2007-11-21 Lars M. Johansen

A fundamental challenge in quantum physics is determining the ground-state properties of many-body systems. Whereas standard approaches, such as variational calculations, consist of writing down a wave function ansatz and minimizing over…

Quantum Physics · Physics 2026-04-03 Jie Wang , David Jansen , Irénée Frerot , Marc-Olivier Renou , Victor Magron , Antonio Acín

The Watson-Migdal approximation scheme to take into account final state interactions is shown to give the actual threshold momentum dependence of the reaction $pp \to pp\pi^0$. However, by an explicit plane wave replacement of the final…

Nuclear Theory · Physics 2009-10-31 J. A. Niskanen

Many rotational invariants for crystal structure representations have been used to describe the structure-property relationship by machine learning. The machine learning interatomic potential (MLIP) is one of the applications of rotational…

Computational Physics · Physics 2019-07-03 Atsuto Seko , Atsushi Togo , Isao Tanaka

Rotating wave approximation in a quantum spin system driven by a linearly polarized alternating magnetic field with quadrupole interaction presents is investigated in detail in this paper. The conventional way to employ the rotating wave…

Quantum Physics · Physics 2020-10-16 Wenkui Ding , Xiaoguang Wang

We explore experimentally quantum non-demolition (QND) measurements of atomic spin in a hot potassium vapor in the presence of spin-exchange relaxation. We demonstrate a new technique for back-action evasion by stroboscopic modulation of…

Quantum Physics · Physics 2015-05-20 G. Vasilakis , V. Shah , M. V. Romalis

Single-reference coupled-cluster theory is an accurate and affordable computational method for the nuclear many-body problem. For open-shell nuclei, the reference state typically breaks rotational invariance and angular momentum must be…

Nuclear Theory · Physics 2022-08-03 G. Hagen , S. J. Novario , Z. H. Sun , T. Papenbrock , G. R. Jansen , J. G. Lietz , T. Duguet , A. Tichai

Continuous-variable (CV) quantum computing is a promising candidate for quantum computation because it can, even with one mode, utilize infinite-dimensional Hilbert spaces and can efficiently handle continuous values. Although photonic…

State estimation in robotic systems presents significant challenges, particularly due to the prevalence of multimodal posterior distributions in real-world scenarios. One effective strategy for handling such complexity is to compute maximum…

Robotics · Computer Science 2026-01-27 Min-Won Seo , Solmaz S. Kia

We propose a simple variational wave function that captures the correct ground state energy of the spin-1 Heisenberg chain model to within 0.04\%. The wave function is written in the matrix product state (MPS) form with the bond dimension…

Strongly Correlated Electrons · Physics 2020-08-19 Jintae Kim , Minsoo Kim , Naoki Kawashima , Jung Hoon Han , Hyun-Yong Lee

The purpose of this text is to give a self-contained description of the basic theory of the projector augmented-wave (PAW) method, as well as most of the details required to make the method work in practice. These two topics are covered in…

Materials Science · Physics 2009-10-13 Carsten Rostgaard

Quantum simulation of materials is a promising application area of quantum computers. To practically realize this promise, we must reduce quantum resources while maintaining accuracy. In electronic structure calculations on classical…