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Related papers: A quantum algorithm for obtaining the energy spect…

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We present a model for quantum computation using n steady 3-level atoms or 3-level quantum dots, kept inside a quantum electro-dynamics (QED) cavity. Our model allows one-qubit operations and the two-qubit controlled-NOT gate as required…

Quantum Physics · Physics 2007-05-23 Prabhakar Pradhan , M. P. Anantram , Kang L. Wang

In this Letter, we construct the quantum algorithms for the Simon problem and the period-finding problem, which do not require initializing the auxiliary qubits involved in the process of functional evaluation but are as efficient as the…

Quantum Physics · Physics 2007-05-23 Dong Pyo Chi , Jeong San Kim , Soojoon Lee

Computing excitation spectra of quantum many-body systems is a promising avenue to demonstrate the practical utility of current noisy quantum devices, especially as we move toward the ``megaquop'' regime. For this task, here we introduce a…

Quantum Physics · Physics 2026-04-16 Ji-Yao Chen , Bochen Huang , D. L. Zhou , Norbert Schuch , Chenfeng Cao , Muchun Yang

Efficient characterization of highly entangled multi-particle systems is an outstanding challenge in quantum science. Recent developments have shown that a modest number of randomized measurements suffices to learn many properties of a…

Quantum Physics · Physics 2022-12-13 Katherine Van Kirk , Jordan Cotler , Hsin-Yuan Huang , Mikhail D. Lukin

Measurements are a primitive for characterizing quantum systems. Reducing the time taken to perform a measurement may be beneficial in many areas of quantum information processing. We show that permuting the eigenvalues of the state matrix…

Quantum Physics · Physics 2015-02-10 Joshua Combes , Aaron Denney , Howard M. Wiseman

We present a method to estimate the probabilities of outcomes of a quantum observable, its mean value, and higher moments by measuring any other observable. This method is general and can be applied to any quantum system. In the case of…

Quantum Physics · Physics 2023-08-16 Dominik Šafránek , Dario Rosa

We consider the question of how correlated the system hardness is between classical algorithms of electronic structure theory in ground state estimation and quantum algorithms. To define the system hardness for classical algorithms we…

We study a two-level impurity coupled locally to a quantum gas on an optical lattice. For state-dependent interactions between the impurity and the gas, we show that its evolution encodes information on the local excitation spectrum of gas…

Quantum Gases · Physics 2018-10-17 Ayaka Usui , Berislav Buča , Jordi Mur-Petit

We develop and analyze a fault-tolerant quantum algorithm for computing $n$-th order response properties necessary for analysis of non-linear spectroscopies of molecular and condensed phase systems. We use a semi-classical description in…

Quantum Physics · Physics 2024-04-23 Tyler Kharazi , Torin F. Stetina , Liwen Ko , Guang Hao Low , K. Birgitta Whaley

Quantum technology has the potential to revolutionize how we acquire and process experimental data to learn about the physical world. An experimental setup that transduces data from a physical system to a stable quantum memory, and…

We introduce a technique for recovering noise-free observables in noisy quantum systems by combining the results of many slightly different experiments. Our approach is applicable to a variety of quantum systems but we illustrate it with…

Quantum Physics · Physics 2019-01-30 Matthew Otten , Stephen Gray

A generalized quantum search algorithm, where phase inversions for the marked state and the prepared state are replaced by $\pi/2$ phase rotations, is realized in a 2-qubit NMR heteronuclear system. The quantum algorithm searches a marked…

Quantum Physics · Physics 2009-11-06 G. L. Long , H. Y. Yan , Y. S. Li , C. C. Tu , J. X. Tao , H. M. Chen , M. L. Liu , X. Zhang , J. Luo , L. Xiao , X. Z. Zeng

Quantum thermodynamic process involves manipulating and controlling quantum states to extract energy or perform computational tasks with high efficiency. There is still no efficientgeneral method to theoretically quantify the effect of the…

Quantum Physics · Physics 2024-06-21 Ming-Xing Luo

Given a finite number of copies of an unknown qubit state that have already been measured optimally, can one still extract any information about the original unknown state? We give a positive answer to this question and quantify the…

Quantum Physics · Physics 2015-05-13 Peter Rapcan , John Calsamiglia , Ramon Munoz-Tapia , Emilio Bagan , Vladimir Buzek

A new method for quantum computation in the presence of detected spontaneous emission is proposed. The method combines strong and fast (dynamical decoupling) pulses and a quantum error correcting code that encodes $n$ logical qubits into…

Quantum Physics · Physics 2009-11-10 K. Khodjasteh , D. A. Lidar

After a general introduction to nuclear magnetic resonance (NMR), we give the basics of implementing quantum algorithms. We describe how qubits are realized and controlled with RF pulses, their internal interactions, and gradient fields. A…

Quantum state tomography is a technique in quantum information science used to reconstruct the density matrix of an unknown quantum state, providing complete information about the quantum state. It is of significant importance in fields…

Quantum Physics · Physics 2025-07-23 Wenlong Zhao , Da Zhang , Huili Zhang , Haifeng Yu , Zhang-qi Yin

We transform the problem of solving linear system of equations $A\mathbf{x}=\mathbf{b}$ to a problem of finding the right singular vector with singular value zero of an augmented matrix $C$, and present two quantum algorithms for solving…

Quantum Physics · Physics 2023-01-20 Hefeng Wang , Hua Xiang

A key requirement to perform simulations of large quantum systems on near-term quantum hardware is the design of quantum algorithms with short circuit depth that finish within the available coherence time. A way to stay within the limits of…

Entanglement lies at the core of quantum algorithms designed to solve problems that are intractable by classical approaches. One such algorithm, quantum annealing (QA), provides a promising path to a practical quantum processor. We have…