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Related papers: Restoring broken symmetries using oracles

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The standard quantum search algorithm lacks a feature, enjoyed by many classical algorithms, of having a fixed-point, i.e. a monotonic convergence towards the solution. Here we present two variations of the quantum search algorithm, which…

Quantum Physics · Physics 2007-05-23 Lov K. Grover , Apoorva Patel , Tathagat Tulsi

A geometric approach to formulate the uncertainty principle between quantum observables acting on an $N$-dimensional Hilbert space is proposed. We consider the fidelity between a density operator associated with a quantum system and a…

Quantum Physics · Physics 2015-06-16 G. M. Bosyk , T. M. Osán , P. W. Lamberti , M. Portesi

Entanglement is one of the fundamental properties of a quantum state and is a crucial differentiator between classical and quantum computation. There are many ways to define entanglement and its measure, depending on the problem or…

Quantum Physics · Physics 2025-01-07 Andrii Semenov , Niall Murphy , Simone Patscheider , Alessandra Bernardi , Elena Blokhina

We propose a new treatment for the quantum three-body problem. It is based on an expansion of the wave function on harmonic oscillator functions with different sizes in the Jacobi coordinates. The matrix elements of the Hamiltonian can be…

Quantum Physics · Physics 2020-04-17 B. Silvestre-Brac , R. Bonnaz , C. Semay , F. Brau

Quantum algorithms have been developed for efficiently solving linear algebra tasks. However, they generally require deep circuits and hence universal fault-tolerant quantum computers. In this work, we propose variational algorithms for…

Quantum Physics · Physics 2021-12-28 Xiaosi Xu , Jinzhao Sun , Suguru Endo , Ying Li , Simon C. Benjamin , Xiao Yuan

Variational quantum algorithms are a class of techniques intended to be used on near-term quantum computers. The goal of these algorithms is to perform large quantum computations by breaking the problem down into a large number of shallow…

Quantum Physics · Physics 2023-03-24 Ryan Shaffer , Lucas Kocia , Mohan Sarovar

We explore the preparation of specific nuclear states on gate-based quantum hardware using variational algorithms. Large scale classical diagonalization of the nuclear shell model have reached sizes of $10^9 - 10^{10}$ basis states, but are…

Nuclear Theory · Physics 2022-07-11 I. Stetcu , A. Baroni , J. Carlson

The generation of continuous-variable multipartite entangled states is important for several protocols of quantum information processing and communication, such as one-way quantum computation or controlled dense coding. In this article we…

System of 1/2 spin particles is observed repeatedly using Stern-Gerlach apparatuses with rotated orientations. Synthesis of such non-commuting observables is analyzed using maximum likelihood estimation as an example of quantum state…

Quantum Physics · Physics 2009-10-31 Z. Hradil , J. Summhammer , G. Badurek , H. Rauch

We consider the problem of constructing quantum operations or channels, if they exist, that transform a given set of quantum states $\{\rho_1, \dots, \rho_k\}$ to another such set $\{\hat\rho_1, \dots, \hat\rho_k\}$. In other words, we must…

Numerical Analysis · Mathematics 2014-07-25 Yuen-Lam Cheung , Dmitriy Drusvyatskiy , Chi-Kwong Li , Diane Pelejo , Henry Wolkowicz

How to implement quantum oracle with limited resources raises concerns these days. We design two ancilla-adjustable and efficient algorithms to synthesize SAT-oracle, the key component in solving SAT problems. The previous work takes 2m-1…

Quantum Physics · Physics 2022-06-10 Shuai Yang , Wei Zi , Bujiao Wu , Cheng Guo , Jialin Zhang , Xiaoming Sun

Recent developments in atomic physics have enabled the experimental generation of many-body entangled states to boost the performance of quantum sensors beyond the Standard Quantum Limit (SQL). This limit is imposed by the inherent…

Quantum Physics · Physics 2024-06-19 Simone Colombo , Edwin Pedrozo-Peñafiel , Vladan Vuletić

One of the most promising applications of noisy intermediate-scale quantum computers is the simulation of molecular Hamiltonians using the variational quantum eigensolver. We show that encoding symmetries of the simulated Hamiltonian in the…

We give a new quantum circuit approximation of quantum multiplexors based on the idea of complexity theory oracles. As an added bonus, our multiplexor approximation immediately gives a quantum circuit approximation of diagonal unitary…

Quantum Physics · Physics 2009-02-17 Robert R. Tucci

Selecting a set of basis states is a common task in quantum computing, in order to increase and/or evaluate their probabilities. This is similar to designing WHERE clauses in classical database queries. Even though one can find heuristic…

Quantum Physics · Physics 2021-06-16 Austin Gilliam , Marco Pistoia , Constantin Gonciulea

The fact that the computational cost of simulating a many-body quantum system on a computer increases with the amount of entanglement has been considered as the major bottleneck for simulating its out-of-equilibrium dynamics. Some aspects…

Statistical Mechanics · Physics 2019-06-12 Jacopo Surace , Marco Piani , Luca Tagliacozzo

This thesis aims to establish notions of symmetry for quantum states and channels as well as describe algorithms to test for these properties on quantum computers. Ideally, the work will serve as a self-contained overview of the subject. We…

Quantum Physics · Physics 2023-05-25 Margarite L. LaBorde

We consider a generalization of the standard oracle model in which the oracle acts on the target with a permutation selected according to internal random coins. We describe several problems that are impossible to solve classically but can…

Quantum Physics · Physics 2013-10-09 Aram W. Harrow , David J. Rosenbaum

Quantum oracles are widely adopted in problems, like query oracle in Grover's algorithm, cipher in quantum cryptanalytic and data encoder in quantum machine learning. Notably, the bit-flip oracle, capable of flipping the state based on a…

Quantum Physics · Physics 2025-12-02 Buji Xu , Junhong Nie , Xiaoming Sun

We study the problem of learning an unknown graph provided via an oracle using a quantum algorithm. We consider three query models. In the first model ("OR queries"), the oracle returns whether a given subset of the vertices contains any…

Quantum Physics · Physics 2021-01-26 Ashley Montanaro , Changpeng Shao