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Quantum advantage is the core of quantum computing. Grover's search algorithm is the only quantum algorithm with proven advantage to any possible classical search algorithm. However, realizing this quantum advantage in practice is quite…

Quantum Physics · Physics 2023-06-21 Jian Leng , Fan Yang , Xiang-Bin Wang

Shor's powerful quantum algorithm for factoring represents a major challenge in quantum computation and its full realization will have a large impact on modern cryptography. Here we implement a compiled version of Shor's algorithm in a…

Despite being one of the hallmarks of quantum physics, there is a lack of operational interpretations of quantum coherence. Here we provide an operational interpretation of coherence of a quantum system, in terms of the amount of noise that…

Quantum Physics · Physics 2017-04-10 Uttam Singh , Manabendra Nath Bera , Avijit Misra , Arun Kumar Pati

We report on the effects of a simple decoherence model on the quantum search algorithm. Despite its simplicity, the decoherence model is an instructive model that can genuinely imitate realistic noisy environment in many situations. As one…

Quantum Physics · Physics 2019-08-17 JingLing Chen , Dagomir Kaszlikowski , L. C. Kwek , C. H. Oh

Quantum coherence is one of the fundamental properties of quantum mechanics and also acts as a valuable resource for a variety of practical applications, which includes quantum computing and quantum information processing. Evaluating the…

Quantum Physics · Physics 2024-09-16 Yikang Zhu , Zhaofeng Su

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

Decoherence of quantum states is a major hurdle towards scalable and reliable quantum computing. Lower decoherence (i.e., higher fidelity) can alleviate the error correction overhead and obviate the need for energy-intensive noise reduction…

Emerging Technologies · Computer Science 2019-04-10 Abdullah Ash Saki , Mahabubul Alam , Swaroop Ghosh

Due to omnipresent environmental interferences, quantum coherences inevitably undergo irreversible transformations over certain time-scales, thus leading to the loss of encoded information. This process, known as decoherence, has been a…

Quantum Physics · Physics 2014-06-19 Swathi S. Hegde , T. S. Mahesh

A model for a quantum register $\cal R$ made of $N$ replicas of a $d$-dimensional quantum system (cell) coupled with the environment, is studied by means of a Born-Markov Master Equation (ME). Dissipation and decoherence are discussed in…

Quantum Physics · Physics 2011-07-19 Paolo Zanardi

Quantum coherence, the physical property underlying fundamental phenomena such as multi-particle interference and entanglement, has emerged as a valuable resource upon which exotic modern technologies are founded. In general, the most…

Characterizing and mitigating errors in current noisy intermediate-scale devices is important to improve performance of next generations of quantum hardware. In order to investigate the importance of the different noise mechanisms affecting…

Quantum Physics · Physics 2023-02-14 Gabriele Cenedese , Giuliano Benenti , Maria Bondani

Coherence plays a very important role in Grover search algorithm (GSA). In this paper, we define the normalization coherence N(C), where C is a coherence measurement. In virtue of the constraint of large N and Shannon's maximum entropy…

Quantum Physics · Physics 2022-06-22 Minghua Pan , Haozhen Situ , Shenggen Zheng

The detection and characterization of quantum coherence is of fundamental importance both in the foundations of quantum theory as well as for the rapidly developing field of quantum technologies, where coherence has been linked to quantum…

Quantum Physics · Physics 2025-12-18 Rhea Alexander , Michalis Skotiniotis , Daniel Manzano

This paper aims to determine the exact success probability at each step of Shor's algorithm. Although the literature usually provides a lower bound on this probability, we present an improved bound. The derived formulas enable the…

Quantum Physics · Physics 2025-06-17 Ali Abbassi , Lionel Bayle

We present a detailed report on the decoherence of quantum states of continuous variable systems under the action of a quantum optical master equation resulting from the interaction with general Gaussian uncorrelated environments. The rate…

Quantum Physics · Physics 2007-05-23 A. Serafini , M. G. A. Paris , F. Illuminati , S. De Siena

Grover's quantum algorithm improves any classical search algorithm. We show how random Gaussian noise at each step of the algorithm can be modelled easily because of the exact recursion formulas available for computing the quantum amplitude…

Quantum Physics · Physics 2009-10-31 B. Pablo-Norman , M. Ruiz-Altaba

We identify a sub-class of BQP that captures certain structural commonalities among many quantum algorithms including Shor's algorithms. This class does not contain all of BQP (e.g. Grover's algorithm does not fall into this class). Our…

Computational Complexity · Computer Science 2015-03-20 Richard J. Lipton , Kenneth W. Regan , Atri Rudra

We study the decoherence of a quantum computer in an environment which is inherently correlated in time and space. We first derive the nonunitary time evolution of the computer and environment in the presence of a stabilizer error…

Quantum Physics · Physics 2007-05-23 E. Novais , Harold U. Baranger

The dynamical evolution of a quantum register of arbitrary length coupled to an environment of arbitrary coherence length is predicted within a relevant model of decoherence. The results are reported for quantum bits (qubits) coupling…

Quantum Physics · Physics 2009-11-07 John H. Reina , Luis Quiroga , Neil F. Johnson

We investigate the generic aspects of quantum coherence guided by the concentration of measure phenomenon. We find the average relative entropy of coherence of pure quantum states sampled randomly from the uniform Haar measure and show that…

Quantum Physics · Physics 2016-03-30 Uttam Singh , Lin Zhang , Arun Kumar Pati