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Overcoming the influence of noise and imperfections in quantum devices is one of the main challenges for viable quantum applications. In this article, we present different protocols, which we denote as "superposed quantum error mitigation",…

Quantum computing has noteworthy speedup over classical computing by taking advantage of quantum parallelism, i.e., the superposition of states. In particular, quantum search is widely used in various computationally hard problems. Grover's…

Quantum Physics · Physics 2021-03-29 Ji Liu , Huiyang Zhou

The imperfections of a receiver's detector affect the performance of two-way continuous-variable quantum key distribution protocols and are difficult to adjust in practical situations. We propose a method to improve the performance of…

Quantum Physics · Physics 2014-02-24 Yi-Chen Zhang , Zhengyu Li , Christian Weedbrook , Song Yu , Wanyi Gu , Maozhu Sun , Xiang Peng , Hong Guo

Quantum Amplitude Estimation (QAE) -- a technique by which the amplitude of a given quantum state can be estimated with quadratically fewer queries than by standard sampling -- is a key sub-routine in several important quantum algorithms,…

Quantum Physics · Physics 2020-06-26 Eric G. Brown , Oktay Goktas , W. K. Tham

Most of the schemes for "noiseless" amplification of coherent states, which have recently been attracting theoretical and experimental interest, share a common trait: the amplification is not truly noiseless, or perfect, for non-zero…

Quantum Physics · Physics 2018-11-22 Vedran Dunjko , Erika Andersson

Quantum computing (QC) emulators, which simulate quantum algorithms on classical hardware, are indispensable platforms for testing quantum algorithms before scalable quantum computers become widely available. A critical challenge in QC…

Quantum Physics · Physics 2025-04-03 Seonghyun Choi , Kyeongwon Lee , Jongin Choi , Woojoo Lee

Grover's algorithm is a fundamental quantum algorithm that achieves a quadratic speedup for unstructured search problems of size $N$. Recent studies have reformulated this task as a maximization problem on the unitary manifold and solved it…

Quantum Physics · Physics 2026-04-06 Zhijian Lai , Dong An , Jiang Hu , Zaiwen Wen

The decoherence effect on Grover algorithm has been studied numerically through a noise modelled by a depolarizing channel. Two types of error are introduced characterizing the qubit time evolution and gate application, so the noise is…

Quantum Physics · Physics 2008-01-09 Pedro J. Salas

Given a parameterized quantum circuit such that a certain setting of these real-valued parameters corresponds to Grover's celebrated search algorithm, can a variational algorithm recover these settings and hence learn Grover's algorithm? We…

Quantum Physics · Physics 2019-01-02 Mauro E. S. Morales , Timur Tlyachev , Jacob Biamonte

Modelling non-linear activation functions on quantum computers is vital for quantum neurons employed in fully quantum neural networks, however, remains a challenging task. We introduce an amplitude-based implementation for approximating…

Quantum Physics · Physics 2023-02-09 Jonas Koppe , Mark-Oliver Wolf

The research community has been actively working on the realization of quantum computer. But the large scale commercial quantum computers are not a reality yet quantum computing field has become richer by day with the advent of algorithms…

Quantum Physics · Physics 2021-04-06 Ayan Chattopadhyay , Vikram Menon

There are quantum procedures that encode the solutions to a problem in the phases of quantum amplitudes. This happens in some quantum optimization algorithms in which the value of a function to be maximized or minimized is represented by a…

Quantum Physics · Physics 2025-11-24 Pranjal Agarwal , Nada Ali , Mark Hillery

Quantum algorithms and circuits can, in principle, outperform the best non-quantum (classical) techniques for some hard computational problems. However, this does not necessarily lead to useful applications. To gauge the practical…

Quantum Physics · Physics 2007-05-23 George F. Viamontes , Igor L. Markov , John P. Hayes

The Grover search algorithm is a pivotal advancement in quantum computing, promising a remarkable speedup over classical algorithms in searching unstructured large databases. Here, we report results for the implementation and…

Quantum Physics · Physics 2025-01-14 M. AbuGhanem

We find that reinforcement exponentially reduces computation time of the quantum search problem from $\sqrt{D}$ to $\ln D$ in a $D$-dimensional system. Therefor, a reinforced quantum search is expected to exhibit an exponentially larger…

Quantum Physics · Physics 2026-04-07 Marjan Homayouni-Sangari , Abolfazl Ramezanpour

Amplification plays a key role in classical communication protocols, where it compensates the unavoidable loss of the signal. However, when we enter the quantum domain this approach starts being problematic as the standard kinds of…

Quantum Physics · Physics 2014-07-30 Petr Marek , Radim Filip

A simpler quantum counting algorithm based on amplitude amplification is presented. This algorithm is bounded by O(sqrt(N/M)) calls to the controlled-Grover operator where M is the number of marked states and N is the total number of states…

Quantum Physics · Physics 2019-10-11 C. R. Wie

Medium-scale quantum devices that integrate about hundreds of physical qubits are likely to be developed in the near future. However, such devices will lack the resources for realizing quantum fault tolerance. Therefore, the main challenge…

Quantum Physics · Physics 2021-12-24 Chao Song , Jing Cui , H. Wang , J. Hao , H. Feng , Ying Li

Quantum computers use the quantum interference of different computational paths to enhance correct outcomes and suppress erroneous outcomes of computations. In effect, they follow the same logical paradigm as (multi-particle)…

Quantum Physics · Physics 2007-05-23 R. Cleve , A. Ekert , L. Henderson , C. Macchiavello , M. Mosca

The main ideas of quantum error correction are introduced. These are encoding, extraction of syndromes, error operators, and code construction. It is shown that general noise and relaxation of a set of 2-state quantum systems can always be…

Quantum Physics · Physics 2007-05-23 A. M. Steane