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Related papers: Excited State TBA for the $\phi_{2,1}$ perturbed $…

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We present a stable and systematically improvable quantum Monte Carlo (QMC) approach to calculating excited-state energies, which we implement using our fast randomized iteration method for the full configuration interaction problem…

Computational Physics · Physics 2023-10-03 Samuel M. Greene , Robert J. Webber , James E. T. Smith , Jonathan Weare , Timothy C. Berkelbach

The excess entanglement resulting from exciting a finite number of quasiparticles above the ground state of a free integrable quantum field theory has been investigated quite extensively in the literature. It has been found that it takes a…

High Energy Physics - Theory · Physics 2023-01-18 Luca Capizzi , Olalla A. Castro-Alvaredo , Cecilia De Fazio , Michele Mazzoni , Lucía Santamaría-Sanz

Excited state contamination remains one of the most challenging sources of systematic uncertainty to control in lattice QCD calculations of nucleon matrix elements and form factors: early time separations are contaminated by excited states…

We present a first principles strategy for developing state-specific density functional approximations for excited states. We first clarify why approaches based on conventional ground state approximations miss density-driven correlations,…

Chemical Physics · Physics 2025-06-09 Tim Gould , Stephen G Dale , Leeor Kronik , Stefano Pittalis

We investigate an extension of excited state mean-field theory in which the energy expression is augmented with density functional components in an effort to include the effects of weak electron correlations. The approach remains…

Chemical Physics · Physics 2020-02-05 Luning Zhao , Eric Neuscamman

The quantum-classical correspondence between local minima on the classical energy landscape and excited eigenstates in the energy spectrum is studied within the context of many-body quantum spin systems. In mean-field approximations of a…

Disordered Systems and Neural Networks · Physics 2023-06-23 Yang Wei Koh

This work is concerned with the excited state quantum phase transitions (ESQPTs) defined in Ann.Phys. 323, 1106 (2008). In many-body models that exhibit such transitions, the ground state quantum phase transition (QPT) occurs in parallel…

Statistical Mechanics · Physics 2018-01-08 Francisco Pérez-Bernal , Lea F. Santos

This paper presents a nonperturbative treatment of strong-coupling induced effects in atom-field systems which cannot be seen in traditional perturbative treatments invoking compromising assumptions such as the Born-Markov, rotating wave or…

Quantum Physics · Physics 2020-02-25 Jen-Tsung Hsiang , Bei-Lok Hu

The series of articles [Ann. Phys. 345, 73 (2014) and 356, 57 (2015)] devoted to excited-state quantum phase transitions (ESQPTs) in systems with $f=2$ degrees of freedom is continued by studying the interacting boson model of nuclear…

Quantum Physics · Physics 2019-06-26 Michal Macek , Pavel Stránský , Amiram Leviatan , Pavel Cejnar

We present a formulation of excited state mean-field theory in which the derivatives with respect to the wave function parameters needed for wave function optimization (not to be confused with nuclear derivatives) are expressed analytically…

Chemical Physics · Physics 2020-06-24 Luning Zhao , Eric Neuscamman

For a conformal field theory (CFT) deformed by a relevant operator, the entanglement entropy of a ball-shaped region may be computed as a perturbative expansion in the coupling. A similar perturbative expansion exists for excited states…

High Energy Physics - Theory · Physics 2016-05-04 Antony J. Speranza

We analyze excited-state quantum phase transitions (ESQPTs) in three schematic (integrable and nonintegrable) models describing a single-mode bosonic field coupled to a collection of atoms. It is shown that the presence of the ESQPT in…

Quantum Physics · Physics 2015-05-20 P. Perez-Fernandez , P. Cejnar , J. M. Arias , J. Dukelsky , J. E. Garcia-Ramos , A. Relano

Building on our recent study [https://doi.org/10.1021/acs.jpclett.3c02052, J. Phys. Chem. Lett. 14, 8780 (2023)], we explore the generalization of the ground-state Kohn-Sham (KS) formalism of density-functional theory (DFT) to the (singlet)…

Chemical Physics · Physics 2025-04-15 Pierre-François Loos , Sara Giarrusso

While the variational principle for excited-state energies leads to a route to obtaining excited-state densities from time-dependent density functional theory, relatively little attention has been paid to the quality of the resulting…

Chemical Physics · Physics 2025-09-12 Anna Baranova , Neepa T. Maitra

We optically probe the spectrum of ground and excited state transitions of an individual, electrically tunable self-assembled quantum dot molecule. Photocurrent absorption measurements show that the spatially direct neutral exciton…

Mesoscale and Nanoscale Physics · Physics 2011-11-15 K. Müller , G. Reithmaier , E. C. Clark , V. Jovanov , M. Bichler , H. J. Krenner , M. Betz , G. Abstreiter , J. J. Finley

Determining quantum excited states is crucial across physics and chemistry but presents significant challenges for variational methods, primarily due to the need to enforce orthogonality to lower-energy states, often requiring…

Quantum Physics · Physics 2025-05-01 Shi-Xin Zhang , Lei Wang

We consider the field theory describing the scaling limit of the Potts quantum spin chain using a combination of two approaches. The first is the renormalized truncated conformal space approach (TCSA), while the second one is a new…

High Energy Physics - Theory · Physics 2014-09-11 M. Lencses , G. Takacs

We introduce the multistate iterative qubit coupled cluster (MS-iQCC) method, a quantum-inspired algorithm that runs efficiently on classical hardware and is designed to predict both ground and excited electronic states of molecules.…

Chemical Physics · Physics 2026-01-05 Robert A. Lang , Shashank G. Mehendale , Ilya G. Ryabinkin , Artur F. Izmaylov

Variational excited-state density functional theory (DFT) enables the calculation of excited states at a cost comparable to ground-state calculations, but single-configuration approaches often suffer from spin contamination. We implement…

Chemical Physics · Physics 2026-05-28 Michael J. Sahre , Marco Romanelli , Martijn Marsman , Leticia González , Georg Kresse

The computation of excited electronic states is an important application for quantum computers. In this work, we simulate the excited state spectra of four aromatic heterocycles on IBM superconducting quantum computers, focusing on active…

Quantum Physics · Physics 2023-09-19 Maria A. Castellanos , Mario Motta , Julia E. Rice