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We present improved quantum circuit for modular exponentiation of a constant, which is the most expensive operation in Shor's algorithm for integer factorization. While previous work mostly focuses on minimizing the number of qubits or the…

Quantum Physics · Physics 2023-11-28 Xia Liu , Huan Yang , Li Yang

We report the first study using active-orbital-based and adaptive CC($P$;$Q$) approaches to describe excited electronic states. These CC($P$;$Q$) methodologies are applied, alongside their completely renormalized (CR) coupled-cluster (CC)…

Chemical Physics · Physics 2025-01-08 Karthik Gururangan , Jun Shen , Piotr Piecuch

Quantum--Mechanical methods that are both computationally fast and accurate are not yet available for electronic excitations having charge transfer character. In this work, we present a significant step forward towards this goal for those…

Chemical Physics · Physics 2015-06-12 Michele Pavanello , Troy Van Voorhis , Lucas Visscher , Johannes Neugebauer

We present an implementation of relativistic ionization-potential (IP) equation-of-motion coupled-cluster (EOMCC) with up to 3-hole--2-particle (3h2p) excitations that makes use of the molecular mean-field exact two-component (mmfX2C)…

Chemical Physics · Physics 2025-01-10 Stephen H. Yuwono , Run R. Li , Tianyuan Zhang , Xiaosong Li , A. Eugene DePrince

Ge/Si structures with vertically stacked quantum dots are simulated to implement the basic elements of a quantum computer for operation with electron spin states. Elastic-strain fields are simulated using the conjugate gradient method and…

Mesoscale and Nanoscale Physics · Physics 2016-01-05 Yu. N. Morokov , M. P. Fedoruk , A. V. Dvurechenskii , A. F. Zinov'eva , A. V. Nenashev

We present a perturbative triples correction to the relativistic quadratic unitary coupled cluster singles and doubles (qUCCSD) method, denoted as qUCCSD[T]. The method builds upon the Hermitian structure of the unitary ansatz and employs a…

Chemical Physics · Physics 2025-10-08 Kamal Majee , Ján Šimunek , Jozef Noga , Achintya Kumar Dutta

The quantum-computational cost of determining ground state energies through quantum phase estimation depends on the overlap between an easily preparable initial state and the targeted ground state. The Van Vleck orthogonality catastrophe…

In this work we investigate methods to improve the efficiency and scalability of quantum algorithms for quantum chemistry applications. We propose a transformation of the electronic structure Hamiltonian in the second quantization framework…

We propose quantum algorithms for projective ground-state preparation and calculations of the many-body Green's functions directly in frequency domain. The algorithms are based on the linear combination of unitary (LCU) operations and…

Quantum Physics · Physics 2021-12-13 Trevor Keen , Eugene Dumitrescu , Yan Wang

Estimating the ground state energy of a multiparticle system with relative error $\e$ using deterministic classical algorithms has cost that grows exponentially with the number of particles. The problem depends on a number of state…

Quantum Physics · Physics 2013-07-23 Anargyros Papageorgiou , Iasonas Petras , Joseph F. Traub , Chi Zhang

The d+N systems are studied in a three-body model, using phenomenological N-N interactions. The scattering matrices are calculated by using the Kohn-Hulthen variational method. Then, they are analytically continued to complex energies and…

Nuclear Theory · Physics 2014-11-18 Attila Csoto , G. M. Hale

We compute the electric dipole polarizability of 48Ca with an increased precision by including more correlations than in previous studies. Employing the coupled-cluster method we go beyond singles and doubles excitations and include…

Nuclear Theory · Physics 2018-08-01 Mirko Miorelli , Sonia Bacca , Gaute Hagen , Thomas Papenbrock

Coupled cluster methods are widely regarded as the gold standard of computational quantum chemistry as they are perceived to offer the best compromise between computational cost and a high-accuracy resolution of the ground state eigenvalue…

Numerical Analysis · Mathematics 2025-12-03 Muhammad Hassan , Yvon Maday

We introduce a hybrid many-body approach that combines the flexibility of the No-Core Shell Model (NCSM) with the efficiency of Multi-Configurational Perturbation Theory (MCPT) to compute ground- and excited-state energies in arbitrary…

Nuclear Theory · Physics 2018-10-24 Alexander Tichai , Eskendr Gebrerufael , Klaus Vobig , Robert Roth

We calculate for the first time the electric dipole moment (EDM) of the $^6$Li nucleus within the alpha + p + n three-body cluster model using the Gaussian expansion method, assuming the one meson exchange P, CP-odd nuclear forces. It is…

Nuclear Theory · Physics 2015-05-28 Nodoka Yamanaka , Emiko Hiyama

It would be very useful to find a way of reducing excited-state effects in lattice QCD calculations of nucleon structure that has a low computational cost. We explore the use of hybrid interpolators, which contain a nontrivial gluonic…

The accuracy at which total energies of open-shell atoms and organic radicals may be calculated is assessed for selected coupled cluster perturbative triples expansions, all of which augment the coupled cluster singles and doubles (CCSD)…

Chemical Physics · Physics 2016-05-17 Janus Juul Eriksen , Devin A. Matthews , Poul Jørgensen , Jürgen Gauss

Variational quantum eigensolver (VQE) for electronic structure calculations is believed to be one major potential application of near term quantum computing. Among all proposed VQE algorithms, the unitary coupled cluster singles and doubles…

Quantum Physics · Physics 2020-10-13 Rongxin Xia , Sabre Kais

We present a measurement-cost efficient implementation of Strongly-Contracted $N$-Electron Valence Perturbation Theory (SC-NEVPT2) for use on near-term quantum devices. At the heart of our algorithm we exploit the properties of adaptive…

Quantum Physics · Physics 2024-05-27 Aaron Fitzpatrick , N. Walter Talarico , Roberto Di Remigio Eikås , Stefan Knecht

Transitions between different states of matter and their thermodynamic properties are described by the Equation of State (EoS). A universal representation of the EoS of Quantum Chromodynamics (QCD) for the wide range of phase diagram has…

High Energy Physics - Phenomenology · Physics 2023-08-22 Maria Stefaniak , Klaus Werner , Johannes Jahan , Hanna Zbroszczyk