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Quantum computing opens up new possibilities for the simulation of many-body nuclear systems. As the number of particles in a many-body system increases, the size of the space if the associated Hamiltonian increases exponentially. This…

Quantum Physics · Physics 2022-09-19 Isaac Hobday , Paul Stevenson , James Benstead

Theoretical descriptions of excited states of molecular systems in high-energy regimes are crucial for supporting and driving many experimental efforts at light source facilities. However, capturing their complicated correlation effects…

We adapt the robust phase estimation algorithm to the evaluation of energy differences between two eigenstates using a quantum computer. This approach does not require controlled unitaries between auxiliary and system registers or even a…

Quantum Physics · Physics 2021-06-02 A. E. Russo , K. M. Rudinger , B. C. A. Morrison , A. D. Baczewski

We describe a quantum computer based on electrons supported by a helium film and localized laterally by small electrodes just under the helium surface. Each qubit is made of combinations of the ground and first excited state of an electron…

Quantum Physics · Physics 2007-05-23 A. J. Dahm , J. M. Goodkind , I. Karakurt , S. Pilla

A common requirement of quantum simulations and algorithms is the preparation of complex states through sequences of 2-qubit gates. For a generic quantum state, the number of gates grows exponentially with the number of qubits, becoming…

Quantum Physics · Physics 2024-07-08 Matan Ben Dov , David Shnaiderov , Adi Makmal , Emanuele G. Dalla Torre

We propose a general scheme for dissipatively preparing arbitrary pure quantum states on a multipartite qubit register in a finite number of basic control blocks. Our "splitting-subspace" approach relies on control resources that are…

Quantum Physics · Physics 2013-11-19 Giacomo Baggio , Francesco Ticozzi , Lorenza Viola

Quantum computation promises an exponential speedup of certain classes of classical calculations through the preparation and manipulation of entangled quantum states. So far most molecular simulations on quantum computers, however, have…

Quantum Physics · Physics 2020-11-18 LeeAnn M. Sager , Scott E. Smart , David A. Mazziotti

Machine learning has recently emerged as a fruitful area for finding potential quantum computational advantage. Many of the quantum enhanced machine learning algorithms critically hinge upon the ability to efficiently produce states…

Time-dependent response theories are foundational to the development of algorithms that determine quantum properties of electronic excited states of molecules and periodic systems. They are employed in wave-function, density-functional, and…

Chemical Physics · Physics 2022-11-23 Martín A. Mosquera

Approximating ground and a fixed number of excited state energies, or equivalently low order Hamiltonian eigenvalues, is an important but computationally hard problem. Typically, the cost of classical deterministic algorithms grows…

Quantum Physics · Physics 2015-08-10 Stuart Hadfield , Anargyros Papageorgiou

Initialization of mechanical modes in the quantum ground state is crucial for their use in quantum information and quantum sensing protocols. In quantum processors, impurity of the modes' initial state affects the infidelity of subsequent…

Quantum Physics · Physics 2026-05-11 Andraz Omahen , Simon Storz , Marius Bild , Dario Scheiwiller , Matteo Fadel , Yiwen Chu

Quantum systems have an exponentially large degree of freedom in the number of particles and hence provide a rich dynamics that could not be simulated on conventional computers. Quantum reservoir computing is an approach to use such a…

Quantum Physics · Physics 2020-11-11 Keisuke Fujii , Kohei Nakajima

Engineered dissipation provides a powerful route to controlling and stabilizing quantum states in open systems. Superconducting circuits are particularly suited to this approach due to their tunable coupling to dissipative environments.…

Quantum Physics · Physics 2026-05-13 Qihao Guo , Botao Du , Ruichao Ma

Machine learning advances chemistry and materials science by enabling large-scale exploration of chemical space based on quantum chemical calculations. While these models supply fast and accurate predictions of atomistic chemical…

Chemical Physics · Physics 2019-06-25 K. T. Schütt , M. Gastegger , A. Tkatchenko , K. -R. Müller , R. J. Maurer

Simulating chemical systems is highly sought after and computationally challenging, as the number of degrees of freedom increases exponentially with the size of the system. Quantum computers have been proposed as a computational means to…

Excited states of many-body quantum systems play a key role in a wide range of physical and chemical phenomena. Unlike ground states, for which many efficient variational techniques exist, there are few ways to systematically construct…

Quantum Physics · Physics 2025-08-04 D. A. Millar , L. W. Anderson , E. Altamura , O. Wallis , M. E. Sahin , J. Crain , S. J. Thomson

We show that optimal control of the electron dynamics is able to prepare molecular ground states, within chemical accuracy, with evolution times approaching the bounds imposed by quantum mechanics. We propose a specific parameterization of…

Quantum Physics · Physics 2024-02-20 Davide Castaldo , Marta Rosa , Stefano Corni

Excited state decay is examined within the framework of strictly Everett-like (SEL) formulations of quantum mechanics. Even though these formulations were developed for systems of particles as part of a larger system that includes a…

Quantum Physics · Physics 2012-09-18 Jon Geist

Preparation of quantum state lies at the heart of quantum information processing. The greedy algorithm provides a potential method to effectively prepare quantum states. However, the standard greedy algorithm, in general, cannot take the…

Quantum Physics · Physics 2022-07-12 Run-Hong He , Hai-Da Liu , Sheng-Bin Wang , Jing Wu , Shen-Shuang Nie , Zhao-Ming Wang

State-average calculations based on mixture of states are increasingly being exploited across chemistry and physics as versatile procedures for addressing excitations of quantum many-body systems. If not too many states should need to be…