Quantum Information

MRS Bulletin ◽  
2005 ◽  
Vol 30 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Luiz Davidovich

AbstractThe following article is based on the plenary address by Luiz Davidovich (Federal University of Rio de Janeiro), presented on April 14, 2004, at the 2004 MRS Spring Meeting in San Francisco. The field of quantum information is a discipline that aims to investigate methods for characterizing, transmitting, storing, compressing, and computationally utilizing the information carried by quantum states. It owes its rapid development over the last few years to several factors: the ability, developed in several laboratories, to control and measure simple microscopic systems; the discovery of fast quantum algorithms; and the recognition that Moore's law will soon lead to the single-atom limit of elementary computing gates.Cryptography and quantum computing are among the main applications in the field.They rely on the subtle and fundamental properties of the quantum world: the unavoidable disturbance associated with measurement, the superposition principle, and the nonlocal properties of entangled states. Progress in this area is intimately connected to a deep understanding of quantum physics: recent achievements include the experimental demonstration of teleportation and detailed investigations of the role of the environment in the quantum–classical transition. This article reviews basic concepts and recent developments in the field of quantum information, emphasizing the close ties between fundamental research and possible applications.

Author(s):  
Phillip Kaye ◽  
Raymond Laflamme ◽  
Michele Mosca

A computer is a physical device that helps us process information by executing algorithms. An algorithm is a well-defined procedure, with finite description, for realizing an information-processing task. An information-processing task can always be translated into a physical task. When designing complex algorithms and protocols for various information-processing tasks, it is very helpful, perhaps essential, to work with some idealized computing model. However, when studying the true limitations of a computing device, especially for some practical reason, it is important not to forget the relationship between computing and physics. Real computing devices are embodied in a larger and often richer physical reality than is represented by the idealized computing model. Quantum information processing is the result of using the physical reality that quantum theory tells us about for the purposes of performing tasks that were previously thought impossible or infeasible. Devices that perform quantum information processing are known as quantum computers. In this book we examine how quantum computers can be used to solve certain problems more efficiently than can be done with classical computers, and also how this can be done reliably even when there is a possibility for errors to occur. In this first chapter we present some fundamental notions of computation theory and quantum physics that will form the basis for much of what follows. After this brief introduction, we will review the necessary tools from linear algebra in Chapter 2, and detail the framework of quantum mechanics, as relevant to our model of quantum computation, in Chapter 3. In the remainder of the book we examine quantum teleportation, quantum algorithms and quantum error correction in detail. We are often interested in the amount of resources used by a computer to solve a problem, and we refer to this as the complexity of the computation. An important resource for a computer is time. Another resource is space, which refers to the amount of memory used by the computer in performing the computation. We measure the amount of a resource used in a computation for solving a given problem as a function of the length of the input of an instance of that problem.


Author(s):  
Stephen Barnett

We have seen that there is an intimate relationship between probability and information. The values we assign to probabilities depend on the information available, and information is a function of probabilities. This connection makes it inevitable that information will be an important concept in any statistical theory, including thermodynamics and, of course, quantum physics. The probabilistic interpretation of quantum theory has probability amplitudes rather than probabilities as the fundamental quantities. This feature, together with the associated superposition principle, is responsible for intrinsically quantum phenomena and gives quantum information theory its distinctive flavour. We shall see that the quantum rules for dynamical evolution and measurement, together with the existence of entangled states, have important implications for quantum information. They also make it possible to perform tasks which are either impractical or impossible within the classical domain. In describing these we shall make extensive use of simple but fundamental ideas in quantum theory. This chapter introduces the mathematical description of quantum physics and the concepts which will be employed in our study of quantum information.


2021 ◽  
Vol 158 (3-4) ◽  
pp. 7-38
Author(s):  
Tomasz Kuczerski ◽  
Michał Dyszyński

The paper includes basic information over the domain of quantum physics needed to understand basic principles of calculations and operations with the use of quantum computers. Questions of the unit of quantum information – qubit, and the Bloch’s zone are thoroughly explained. The paper is aimed to be an introduction into the world of quantum IT for persons beyond the quantum physics who want to use the quantum algorithms for their scientific researches.


2018 ◽  
Author(s):  
Rajendra K. Bera

It now appears that quantum computers are poised to enter the world of computing and establish its dominance, especially, in the cloud. Turing machines (classical computers) tied to the laws of classical physics will not vanish from our lives but begin to play a subordinate role to quantum computers tied to the enigmatic laws of quantum physics that deal with such non-intuitive phenomena as superposition, entanglement, collapse of the wave function, and teleportation, all occurring in Hilbert space. The aim of this 3-part paper is to introduce the readers to a core set of quantum algorithms based on the postulates of quantum mechanics, and reveal the amazing power of quantum computing.


2021 ◽  
Vol 22 (7) ◽  
pp. 3485
Author(s):  
Marta Osrodek ◽  
Michal Wozniak

Despite recent groundbreaking advances in the treatment of cutaneous melanoma, it remains one of the most treatment-resistant malignancies. Due to resistance to conventional chemotherapy, the therapeutic focus has shifted away from aiming at melanoma genome stability in favor of molecularly targeted therapies. Inhibitors of the RAS/RAF/MEK/ERK (MAPK) pathway significantly slow disease progression. However, long-term clinical benefit is rare due to rapid development of drug resistance. In contrast, immune checkpoint inhibitors provide exceptionally durable responses, but only in a limited number of patients. It has been increasingly recognized that melanoma cells rely on efficient DNA repair for survival upon drug treatment, and that genome instability increases the efficacy of both MAPK inhibitors and immunotherapy. In this review, we discuss recent developments in the field of melanoma research which indicate that targeting genome stability of melanoma cells may serve as a powerful strategy to maximize the efficacy of currently available therapeutics.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1145
Author(s):  
Yuan Zhao ◽  
Xuecheng Zhu ◽  
Wei Jiang ◽  
Huilin Liu ◽  
Baoguo Sun

With the rapid development of global industry and increasingly frequent product circulation, the separation and detection of chiral drugs/pesticides are becoming increasingly important. The chiral nature of substances can result in harm to the human body, and the selective endocrine-disrupting effect of drug enantiomers is caused by differential enantiospecific binding to receptors. This review is devoted to the specific recognition and resolution of chiral molecules by chromatography and membrane-based enantioseparation techniques. Chromatographic enantiomer separations with chiral stationary phase (CSP)-based columns and membrane-based enantiomer filtration are detailed. In addition, the unique properties of these chiral resolution methods have been summarized for practical applications in the chemistry, environment, biology, medicine, and food industries. We further discussed the recognition mechanism in analytical enantioseparations and analyzed recent developments and future prospects of chromatographic and membrane-based enantioseparations.


2016 ◽  
Vol 32 (1) ◽  
Author(s):  
Yuehao Luo ◽  
Xia Xu ◽  
Dong Li ◽  
Wen Song

AbstractWith the rapid development of science and technology, increasing research interests have been focused on environment protection, global warming, and energy shortage. At present, reducing friction force as much as possible has developed into an urgent issue. Sharkskin effect has the potential ability to lower viscous drag on the fluid-solid interface in turbulence, and therefore, how to fabricate bio-inspired sharkskin surfaces is progressively becoming the hot topic. In this review, various methods of fabricating drag reduction surfaces covering biological sharkskin morphology are illustrated and discussed systematically, mainly involving direct bio-replicated, synthetic fabricating, bio/micro-rolling, enlarged solvent-swelling, drag reduction additive low-releasing, trans-scale enlarged three-dimensional fabricating, flexible printing, large-proportional shrunken bio-replicating, ultraviolet (UV) curable painting, and stretching deformed methods. The overview has the potential benefits in better acquainting with the recent research status of fabricating sharkskin surfaces covering the biological morphology.


Radiotekhnika ◽  
2021 ◽  
pp. 106-114
Author(s):  
Y. Kotukh ◽  
T. Okhrimenko ◽  
O. Dyachenko ◽  
N. Rotaneva ◽  
L. Kozina ◽  
...  

Rapid development and advances of quantum computers are contributing to the development of public key cryptosystems based on mathematically complex or difficult problems, as the threat of using quantum algorithms to hack modern traditional cryptosystems is becoming much more real every day. It should be noted that the classical mathematically complex problems of factorization of integers and discrete logarithms are no longer considered complex for quantum calculations. Dozens of cryptosystems were considered and proposed on various complex problems of group theory in the 2000s. One of such complex problems is the problem of the word. One of the first implementations of the cryptosystem based on the word problem was proposed by Magliveras using logarithmic signatures for finite permutation groups and further proposed by Lempken et al. for asymmetric cryptography with random covers. The innovation of this idea is to extend the difficult problem of the word to a large number of groups. The article summarizes the known results of cryptanalysis of the basic structures of the cryptosystem and defines recommendations for ways to improve the cryptographic properties of structures and the use of non-commutative groups as basic structures.


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