REALIZATION OF UNITARY MAPS VIA PROBABILISTIC PROGRAMMABLE QUANTUM PROCESSORS

2003 ◽  
Vol 01 (04) ◽  
pp. 527-541 ◽  
Author(s):  
MÁRIO ZIMAN ◽  
VLADIMÍR BUŽEK
Keyword(s):  
Quantum Information ◽  
Intrinsic Property ◽  
Complete Analysis ◽  
Input State ◽  
Text Processor ◽  
Programmable Processors ◽  
Data Register

We analyze probabilistic realizations of programmable quantum processors that allow us to realize unitary operations on qubits as well as on qudits. Programmable processors are composed of two inputs — the data register and the program register. In the input state of the program register information about the operation that is supposed to be performed on the data is encoded. At the output of the probabilistic processor a measurement over the program register is performed. An intrinsic property of probabilistic processors is that they sometimes fail, but we know when this happens. We present a complete analysis of two processors: (1) The so-called [Formula: see text] processor that is based on a simple controlled-NOT gate. (2) The so-called [Formula: see text] processor that utilizes the quantum-information-distributor circuit.

scholarly journals Robust bidirectional links for photonic quantum networks

2016 ◽  
Vol 2 (1) ◽  
pp. e1500672 ◽  
Author(s):  
Jin-Shi Xu ◽  
Man-Hong Yung ◽  
Xiao-Ye Xu ◽  
Jian-Shun Tang ◽  
Chuan-Feng Li ◽  
...  
Keyword(s):  
Quantum Information ◽  
Optical Fibers ◽  
Degrees Of Freedom ◽  
Quantum Communication ◽  
Communication Theory ◽  
Input State ◽  
Quantum Networks ◽  
Experimental Realization ◽  
Communication Links ◽  
Polarization Maintaining

Optical fibers are widely used as one of the main tools for transmitting not only classical but also quantum information. We propose and report an experimental realization of a promising method for creating robust bidirectional quantum communication links through paired optical polarization-maintaining fibers. Many limitations of existing protocols can be avoided with the proposed method. In particular, the path and polarization degrees of freedom are combined to deterministically create a photonic decoherence-free subspace without the need for any ancillary photon. This method is input state–independent, robust against dephasing noise, postselection-free, and applicable bidirectionally. To rigorously quantify the amount of quantum information transferred, the optical fibers are analyzed with the tools developed in quantum communication theory. These results not only suggest a practical means for protecting quantum information sent through optical quantum networks but also potentially provide a new physical platform for enriching the structure of the quantum communication theory.

scholarly journals Multiqubit entanglement of a general input state

2013 ◽  
Vol 13 (1&2) ◽  
pp. 36-53
Author(s):  
Elizabeth C. Behrman ◽  
James E. Steck
Keyword(s):  
Quantum Information ◽  
Experimental Measurement ◽  
Mixed State ◽  
Input State ◽  
Dynamic Learning ◽  
Entanglement Witness ◽  
State Reconstruction ◽  
Entanglement Measures ◽  
Computational Systems ◽  
Prior State

Measurement of entanglement remains an important problem for quantum information. We present the design and simulation of an experimental method for an entanglement indicator for a general multiqubit state. The system can be in a pure or a mixed state, and it need not be ``close'' to any particular state. The system contains information about its own entanglement; we use dynamic learning methods to map this information onto a single experimental measurement which is our entanglement indicator. Our method does not require prior state reconstruction or lengthy optimization. An entanglement witness emerges from the learning process, beginning with two-qubit systems, and extrapolating this to three, four, and five qubit systems where the entanglement is not well understood. Our independently learned measures for three-qubit systems compare favorably with known entanglement measures. As the size of the system grows the amount of additional training necessary diminishes, raising hopes for applicability to large computational systems.

scholarly journals Entropy Distribution in a Quantum Informational Circuit of Tunable Szilard Engines

Entropy ◽  
2019 ◽  
Vol 21 (10) ◽  
pp. 980 ◽  
Author(s):  
Jose Diazdelacruz
Keyword(s):  
Quantum Information ◽  
Quantum Entanglement ◽  
Single Particle ◽  
Mechanical Systems ◽  
Input State ◽  
Average Output ◽  
Output State ◽  
Input And Output ◽  
Output Force ◽  
The Cost

This paper explores the possibility of extending the existing model of a single-particle Quantum Szilard Engine to take advantage of some features of quantum information for driving typical mechanical systems. It focuses on devices that output mechanical work, extracting energy from a single thermal reservoir at the cost of increasing the entropy of a qubit; the reverse process is also considered. In this alternative, several engines may share the information carried by the same qubit, although its interception will prove completely worthless for any illegitimate user. To this end, multi-partite quantum entanglement is employed. Besides, some changes in the cycle of the standard single-particle Quantum Szilard Engine are described, which lend more flexibility to meeting additional requirements in typical mechanical systems. The modifications allow having qubit input and output states of adjustable entropy. This feature enables the possibility of chaining the qubit between engines so that its output state from one can be used as an input state for another. Finally, another tweak is presented that allows for tuning the average output force of the engine.

Simple quantum information algorithms in cavity QED

2003 ◽  
Vol 50 (6-7) ◽  
pp. 901-913 ◽  
Author(s):  
H. Ollivier ◽  
F. Yamaguchi ◽  
M. Brune ◽  
J. M. Raimond ◽  
S. Haroche ◽  
...  
Keyword(s):  
Quantum Information ◽  
Cavity Qed ◽  
Simple Quantum

Age does not necessarily influence latency of event-related potentials

2014 ◽  
Vol 33 (10) ◽  
pp. 723-727
Author(s):  
M. Westermann ◽  
I. W. Husstedt ◽  
A. Okegwo ◽  
S. Evers
Keyword(s):  
Normal Values ◽  
Rank Correlation ◽  
Event Related Potentials ◽  
Intrinsic Property ◽  
Total Sample ◽  
Oddball Paradigm ◽  
Age Dependent ◽  
Related Potentials ◽  
The Mean ◽  
P3 Component

SummaryEvent-related potentials (ERP) are regarded as age dependent. However, it is not known whether this is an intrinsic property of ERP or an extrinsic factor. We designed a setting in which ERP were evoked using a modified oddball paradigm with highly differentiable and detectable target and non-target stimuli. A total of 98 probands were enrolled in this study. We evaluated the latency and amplitude of the P3 component of visually evoked ERP. The mean P3 latency was 294 ± 28 ms and was not related to age (r = –0.089; p = 0.382; Spearman-rank-correlation). The P3 amplitude was related to age in the total sample (r = –0.323; p = 0.001; Spearmanrank-correlation) but not in the probands under the age of 60 years. There were no significant differences regarding sex. Our findings suggest that ERP are not age dependent if highly differentiable and detectable stimuli are used. This should be considered when normal values of ERP are created for clinical use.

TOURIST BUSINESS DEVELOPMENT IN UKRAINE

2019 ◽  
pp. 39-46
Author(s):  
Stefania Mosiuk ◽  
Igor Mosiuk ◽  
Vladimir Mosiuk
Keyword(s):  
National Economy ◽  
Methodological Approach ◽  
Business Development ◽  
Tourism Industry ◽  
The State ◽  
Complete Analysis ◽  
Resource Potential ◽  
The World ◽  
Potential Resource ◽  
Favorable Conditions

The purpose of the article is to analyze and substantiate the development of tourism business in Ukraine as a priority component of the national economy. The methodology of this study is to use analytical, spatial, geographical, cultural and other methods. This methodological approach provided an opportunity to carry out a complete analysis of the state of the tourism industry of the state and to draw some conclusions.The scientific novelty lies in the coverage of the real and potential resource potential for the development of the recreational and tourism sphere in Ukraine, detailing the measures for the country ‘s entry into the world tourist market. Conclusions. Analyzing the state and prospects of tourism business development in Ukraine, it should be noted that this industry is one of the priority areas for improving the economy of the country. Historical, cultural – ethnographic, gastronomic, sanatorium and resort potentials of the country will lead the country into world leaders of the tourism industry when creating favorable conditions for investment and proper marketing.

The capacity to reprogramme is an intrinsic property of adult somatic cells

2014 ◽  
Author(s):  
Domenico Iuso ◽  
Paola Toschi ◽  
Debora Agata Anzalone ◽  
Marta Czernik ◽  
Grazyna Ewa Ptak ◽  
...  
Keyword(s):  
Somatic Cells ◽  
Intrinsic Property
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