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The simulation of electronic systems is an anticipated application for quantum-centric computers, i.e. heterogeneous architectures where classical and quantum processing units operate in concert. An important application is the computation…

The usual derivations of the S and K matrices for two-particle reactions proceed through the Lippmann-Schwinger equation with formal definitions of the incoming and outgoing scattering states. Here we present an alternative derivation that…

Atomic and Molecular Clusters · Physics 2020-07-15 Y. Alhassid , G. F. Bertsch , P. Fanto

An essential ingredient in many model Hamiltonians, such as the Hubbard model, is the effective electron-electron interaction $U$, which enters as matrix elements in some localized basis. These matrix elements provide the necessary…

Strongly Correlated Electrons · Physics 2019-05-29 Tor Jonas Sjöstrand , Fredrik Nilsson , Christoph Friedrich , Ferdi Aryasetiawan

Hamiltonian truncation is a non-perturbative numerical method for calculating observables of a quantum field theory. The starting point for this method is to truncate the interacting Hamiltonian to a finite-dimensional space of states…

High Energy Physics - Theory · Physics 2022-08-10 Timothy Cohen , Kara Farnsworth , Rachel Houtz , Markus A. Luty

I describe harmonic-oscillator-based effective theory (HOBET) and explore the extent to which the effects of excluded higher-energy oscillator shells can be represented by a contact-gradient expansion in next-to-next-to-leading order…

Nuclear Theory · Physics 2017-08-23 W. C. Haxton

Many problems in robotics involve multiple decision making agents. To operate efficiently in such settings, a robot must reason about the impact of its decisions on the behavior of other agents. Differential games offer an expressive…

Systems and Control · Electrical Eng. & Systems 2020-03-19 David Fridovich-Keil , Ellis Ratner , Lasse Peters , Anca D. Dragan , Claire J. Tomlin

We developed a general theoretical approach and a user-ready computer code that permit to study the dynamics of collisional energy transfer and ro-vibrational energy exchange in complex molecule-molecule collisions. The method is a mixture…

Chemical Physics · Physics 2024-02-06 Carolin Joy , Bikramaditya Mandal , Dulat Bostan , Marie-Lise Dubernet , Dmitri Babikov

We investigate a three-level maser quantum thermal machine in which the system-reservoir interaction is modeled via Unruh-DeWitt type coupling, with one or both reservoirs undergoing relativistic motion relative to the working medium.…

Quantum Physics · Physics 2025-08-21 Tanmoy Pandit , Pritam Chattopadhyay , Kaustav Chatterjee , Varinder Singh

This work develops and illustrates a new method of calculating "chemically accurate" electronic wavefunctions (and energies) via a truncated full configuration interaction (CI) procedure which arguably circumvents the large matrix…

Chemical Physics · Physics 2022-12-21 Stephen J. Cotton

Starting from the full many-body Hamiltonian of interacting electrons the effective self-energy acting on electrons residing in a subspace of the full Hilbert space is derived. This subspace may correspond to, for example, partially filled…

Strongly Correlated Electrons · Physics 2010-10-20 F. Aryasetiawan , J. M. Tomczak , T. Miyake , R. Sakuma

We develop randomized quantum algorithms to simulate quantum collision models, also known as repeated interaction schemes, which provide a rich framework to model various open-system dynamics. The underlying technique involves composing…

Quantum Physics · Physics 2025-08-20 Kushagra Garg , Zeeshan Ahmed , Subhadip Mitra , Shantanav Chakraborty

Quantum circuits have been widely used as a platform to simulate generic quantum many-body systems. In particular, random quantum circuits provide a means to probe universal features of many-body quantum chaos and ergodicity. Some such…

Quantum Physics · Physics 2022-06-20 Yunxiang Liao , Victor Galitski

We derive an effective 1D theory from the Hamiltonian of the 3D system which consists of a mesoscopic conductor and reservoirs. We assume that the many-body interaction have the same magnitude in the conductor as that in the reservoirs, in…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Akira Shimizu , Takayuki Miyadera

Calculating the quantum evolution of a de Sitter universe on superhorizon scales is notoriously difficult. To address this challenge, we introduce the Soft de Sitter Effective Theory (SdSET). This framework holds for superhorizon modes…

High Energy Physics - Theory · Physics 2020-12-30 Timothy Cohen , Daniel Green

The short range repulsion between nucleons is treated by a unitary correlation operator which shifts the nucleons away from each other whenever their uncorrelated positions are within the replusive core. By formulating the correlation as a…

Nuclear Theory · Physics 2009-10-30 H. Feldmeier , T. Neff , R. Roth , J. Schnack

The Similarity Renormalization Group (SRG) is investigated as a powerful yet practical method to modify nuclear potentials so as to reduce computational requirements for calculations of observables. The key feature of SRG transformations…

Nuclear Theory · Physics 2009-12-16 E. D. Jurgenson

We demonstrate that the dynamics of an open quantum system can be calculated efficiently and with predefined error, provided a basis exists in which the system-environment interactions are local and hence obey the Lieb-Robinson bound. We…

Quantum Physics · Physics 2015-03-19 Giulia Gualdi , Christiane P. Koch

The intrinsic dynamics of a system with open decay channels is described by an effective non-Hermitian Hamiltonian which at the same time allows one to find the external dynamics, - reaction cross sections. We discuss ways of incorporating…

Nuclear Theory · Physics 2009-11-07 Alexander Volya , Vladimir Zelevinsky

Interactions from chiral effective field theory have been successfully employed in a broad range of \textit{ab initio} calculations of nuclei and nuclear matter, but it has been observed that most results of few- and many-body calculations…

Nuclear Theory · Physics 2018-08-30 I. Tews , L. Huth , A. Schwenk

The Liouville-Lanczos approach to linear-response time-dependent density-functional theory is generalized so as to encompass electron energy-loss and inelastic X-ray scattering spectroscopies in periodic solids. The computation of virtual…

Materials Science · Physics 2015-06-16 Iurii Timrov , Nathalie Vast , Ralph Gebauer , Stefano Baroni