scholarly journals Robust dynamical decoupling

2012 ◽  
Vol 370 (1976) ◽  
pp. 4748-4769 ◽  
Author(s):  
Alexandre M. Souza ◽  
Gonzalo A. Álvarez ◽  
Dieter Suter
Keyword(s):  
Quantum Information ◽  
Pulse Sequences ◽  
Coherence Time ◽  
Quantum Mechanical ◽  
Quantum Computers ◽  
Dynamical Decoupling ◽  
Quantum Bits ◽  
Quantum Mechanical Systems ◽  
Further Development ◽  
Loss Of Coherence

Quantum computers, which process information encoded in quantum mechanical systems, hold the potential to solve some of the hardest computational problems. A substantial obstacle for the further development of quantum computers is the fact that the lifetime of quantum information is usually too short to allow practical computation. A promising method for increasing the lifetime, known as dynamical decoupling (DD), consists of applying a periodic series of inversion pulses to the quantum bits. In the present review, we give an overview of this technique and compare different pulse sequences proposed earlier. We show that pulse imperfections, which are always present in experimental implementations, limit the performance of DD. The loss of coherence due to the accumulation of pulse errors can even exceed the perturbation from the environment. This effect can be largely eliminated by a judicious design of pulses and sequences. The corresponding sequences are largely immune to pulse imperfections and provide an increase of the coherence time of the system by several orders of magnitude.

Quantum information entropy and squeezing of 𝒫𝒯-symmetric potential

2021 ◽  
Vol 36 (10) ◽  
pp. 2150065
Author(s):  
Aarti Sharma ◽  
Pooja Thakur ◽  
Girish Kumar ◽  
Anil Kumar
Keyword(s):  
Phase Transition ◽  
Quantum Information ◽  
Information Entropy ◽  
Momentum Space ◽  
Quantum Mechanical ◽  
Position Space ◽  
Entropy Squeezing ◽  
Information Theoretic ◽  
Symmetric Potential ◽  
Quantum Mechanical Systems

The information theoretic concepts are crucial to study the quantum mechanical systems. In this paper, the information densities of [Formula: see text]-symmetric potential have been demonstrated and their properties deeply analyzed. The position space and momentum space information entropy is obtained and Bialynicki-Birula–Mycielski inequality is saturated for different parameters of the potential. Some interesting features of information entropy have been discussed. The variation in these entropies is described which gets saturated for specific values of the parameter. These have also been analyzed for the [Formula: see text]-symmetry breaking case. Further, the entropy squeezing phenomenon has been investigated in position space as well as momentum space. Interestingly, [Formula: see text] phase transition conjectures the entropy squeezing in position space and momentum space.

scholarly journals Entanglement Monotones and Measures: An Overview

2017 ◽  
Author(s):  
Volkan Erol
Keyword(s):  
Information Processing ◽  
Theoretical Basis ◽  
Search Algorithm ◽  
Quantum Information Theory ◽  
The Other ◽  
Quantum Mechanical ◽  
Quantum Computers ◽  
Factorization Algorithm ◽  
Entanglement Measures ◽  
Quantum Mechanical Systems

Quantum information theory and quantum computing are theoritical basis of quantum computers. Thanks to entanglement, quantum mechanical systems are provisioned to realize many information processing problems faster than classical counterparts. For example, Shor’s factorization algorithm, Grover’s search algorithm, quantum Fourrier transformation, etc. [1]. Entanglement, is the theoretical basis providing the expected speedups. It can be view in bipartite or multipartite forms. In order to quantify entanglement, some measures are defined. On the other hand, a general and accepted criterion, which can measure the amount of entanglement of multilateral systems, has not yet been found. However, since it must be used in many information processing tasks, the production and processing of multilateral quantum entangled systems is at the top of the hot topics of recent years [5-11]. Much of the work in the basic quantum technologies, such as quantum cryptography, communications, and computers, requires multi-partite entangled systems such as GHZ, W [22,30]. It can be suggested that the quantum entanglement criteria reflects the different properties of the systems. Many recent research has been done in entanglement and its related disciplines like entanglement measures and majorization, etc. [62-71]. In this work, we make an overview of recent research on the topic entanglement monotones/measures with an analitical approach.

scholarly journals Entanglement Monotones and Measures: An Overview

2017 ◽  
Author(s):  
Volkan Erol
Keyword(s):  
Information Theory ◽  
Theoretical Basis ◽  
Search Algorithm ◽  
Short Review ◽  
Quantum Information Theory ◽  
The Other ◽  
Quantum Mechanical ◽  
Quantum Computers ◽  
Factorization Algorithm ◽  
Quantum Mechanical Systems

Quantum information theory and quantum computing are theoritical basis of quantum computers. Thanks to entanglement, quantum mechanical systems are provisioned to realize many information processing problems faster than classical counterparts. For example, Shor’s factorization algorithm, Grover’s search algorithm, quantum Fourrier transformation, etc. Entanglement, is the theoretical basis providing the expected speedups. It can be view in bipartite or multipartite forms. In order to quantify entanglement, some measures are defined. On the other hand, a general and accepted criterion, which can measure the amount of entanglement of multilateral systems, has not yet been found. In this work, we make a short review of recent research on the topic entanglement monotones and measures with an analitical approach.

scholarly journals Arbitrarily Accurate Pulse Sequences for Robust Dynamical Decoupling

2017 ◽  
Vol 118 (13) ◽  
Author(s):  
Genko T. Genov ◽  
Daniel Schraft ◽  
Nikolay V. Vitanov ◽  
Thomas Halfmann
Keyword(s):  
Pulse Sequences ◽  
Dynamical Decoupling

scholarly journals Practical Security of RSA Against NTC-Architecture Quantum Computing Attacks

2021 ◽  
Author(s):  
Kai Li ◽  
Qing-yu Cai
Keyword(s):  
Quantum Computing ◽  
Ion Trap ◽  
Quantum Algorithms ◽  
Coherence Time ◽  
Quantum Computers ◽  
Quantum Time ◽  
Speed Up ◽  
Key Length ◽  
Concurrent Architecture ◽  
Qubit Gate

AbstractQuantum algorithms can greatly speed up computation in solving some classical problems, while the computational power of quantum computers should also be restricted by laws of physics. Due to quantum time-energy uncertainty relation, there is a lower limit of the evolution time for a given quantum operation, and therefore the time complexity must be considered when the number of serial quantum operations is particularly large. When the key length is about at the level of KB (encryption and decryption can be completed in a few minutes by using standard programs), it will take at least 50-100 years for NTC (Neighbor-only, Two-qubit gate, Concurrent) architecture ion-trap quantum computers to execute Shor’s algorithm. For NTC architecture superconducting quantum computers with a code distance 27 for error-correcting, when the key length increased to 16 KB, the cracking time will also increase to 100 years that far exceeds the coherence time. This shows the robustness of the updated RSA against practical quantum computing attacks.

scholarly journals A Scheme for Controlled Cyclic Asymmetric Remote State Preparation in Noisy Environment

2021 ◽  
Vol 11 (4) ◽  
pp. 1405
Author(s):  
Nan Zhao ◽  
Tingting Wu ◽  
Yan Yu ◽  
Changxing Pei
Keyword(s):  
Quantum Information ◽  
Information Transmission ◽  
Remote State Preparation ◽  
Quantum Computers ◽  
Noisy Environment ◽  
State Preparation ◽  
Channel Expression ◽  
Actual Environment ◽  
The Impact ◽  
Multi Mode

As research on quantum computers and quantum information transmission deepens, the multi-particle and multi-mode quantum information transmission has been attracting increasing attention. For scenarios where multi-parties transmit sequentially increasing qubits, we put forward a novel (N + 1)-party cyclic remote state preparation (RSP) protocol among an arbitrary number of players and a controller. Specifically, we employ a four-party scheme in the case of a cyclic asymmetric remote state preparation scheme and demonstrate the feasibility of the scheme on the IBM Quantum Experience platform. Furthermore, we present a general quantum channel expression under different circulation directions based on the n-party. In addition, considering the impact of the actual environment in the scheme, we discuss the feasibility of the scheme affected by different noises.

Sign in / Sign up

Export Citation Format

Share Document