scholarly journals Rapid and robust generation of Einstein-–Podolsky–-Rosen pairs with spin chains

2018 ◽  
Vol 18 (3&4) ◽  
pp. 247-264
Author(s):  
Kieran N. Wilkinson ◽  
Marta P. Estarellas ◽  
Timothy P. Spiller ◽  
Irene D'Amico
Keyword(s):  
Quantum Information Processing ◽  
Bell State ◽  
Spin Chains ◽  
High Fidelity ◽  
Coupling Ratio ◽  
Einstein Podolsky Rosen ◽  
Characteristic Values ◽  
Natural Dynamics ◽  
Diagonal Disorder ◽  
Very High

We investigate the ability of dimerized spin chains with defects to generate EPR pairs to very high fidelity through their natural dynamics. We propose two protocols based on different initializations of the system, which yield the same maximally entangled Bell state after a characteristic time. This entangling time can be varied through engineering the weak/strong couplings' ratio of the chain, with larger values giving rise to an exponentially faster quantum entangling operation. We demonstrate that there is a set of characteristic values of the coupling, for which the entanglement generated remains extremely high. We investigate the robustness of both protocols to diagonal and off-diagonal disorder. Our results demonstrate extremely strong robustness to both perturbation types, up to strength of 50\% of the weak coupling. Robustness to disorder can be further enhanced by increasing the coupling ratio. The combination of these properties makes the use of our proposed device suitable for the rapid and robust generation of Bell states in quantum information processing applications.

scholarly journals Generation and robustness of quantum entanglement in spin graphs

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Jan Riegelmeyer ◽  
Dan Wignall ◽  
Marta P. Estarellas ◽  
Irene D’Amico ◽  
Timothy P. Spiller
Keyword(s):  
Quantum Information Processing ◽  
Bell State ◽  
Spin Chains ◽  
Coupling Scheme ◽  
High Fidelity ◽  
Coupling Ratio ◽  
Entanglement Generation ◽  
Fabrication Errors ◽  
Coupling Strengths ◽  
Hardware Platforms

AbstractEntanglement is a crucial resource for quantum information processing, and so protocols to generate high-fidelity entangled states on various hardware platforms are in demand. While spin chains have been extensively studied to generate entanglement, graph structures also have such potential; however, only a few classes of graphs have been explored for this specific task. In this paper, we apply a particular coupling scheme involving two different coupling strengths to a graph of two interconnected $$3\times 3$$ 3 × 3 square graphs such that it effectively contains three defects. We show how this structure allows generation of a Bell state whose fidelity depends on the chosen coupling ratio. We apply partitioned graph theory in order to reduce the dimension of the graph and show that, using a reduced graph or a reduced chain, we can still simulate the same protocol with identical dynamics. Finally, we investigate how fabrication errors affect the entanglement generation protocol and how the different equivalent structures are affected, finding that for some specific coupling ratios they are extremely robust.

scholarly journals FEBID 3D-Nanoprinting at Low Substrate Temperatures: Pushing the Speed While Keeping the Quality

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1527
Author(s):  
Jakob Hinum-Wagner ◽  
David Kuhness ◽  
Gerald Kothleitner ◽  
Robert Winkler ◽  
Harald Plank
Keyword(s):  
Volume Growth ◽  
Point Of View ◽  
High Fidelity ◽  
Direct Write ◽  
General Picture ◽  
3D Space ◽  
Design Flexibility ◽  
Substrate Temperatures ◽  
Very High ◽  
Comprehensive Discussion

High-fidelity 3D printing of nanoscale objects is an increasing relevant but challenging task. Among the few fabrication techniques, focused electron beam induced deposition (FEBID) has demonstrated its high potential due to its direct-write character, nanoscale capabilities in 3D space and a very high design flexibility. A limitation, however, is the low fabrication speed, which often restricts 3D-FEBID for the fabrication of single objects. In this study, we approach that challenge by reducing the substrate temperatures with a homemade Peltier stage and investigate the effects on Pt based 3D deposits in a temperature range of 5–30 °C. The findings reveal a volume growth rate boost up to a factor of 5.6, while the shape fidelity in 3D space is maintained. From a materials point of view, the internal nanogranular composition is practically unaffected down to 10 °C, followed by a slight grain size increase for even lower temperatures. The study is complemented by a comprehensive discussion about the growth mechanism for a more general picture. The combined findings demonstrate that FEBID on low substrate temperatures is not only much faster, but practically free of drawbacks during high fidelity 3D nanofabrication.

QUANTUM AUTHENTICATION USING ENTANGLED STATES

2004 ◽  
Vol 15 (04) ◽  
pp. 609-617 ◽  
Author(s):  
XIAOYU LI ◽  
HOWARD BARNUM
Keyword(s):  
Bell State ◽  
Authentication Scheme ◽  
Entangled States ◽  
Bell State Measurement ◽  
Epr Pairs ◽  
State Measurement ◽  
Quantum Authentication ◽  
Einstein Podolsky Rosen

A quantum authentication scheme is presented in this paper. Two parties share Einstein-Podolsky-Rosen(EPR) pairs previously as the identification token. They create auxiliary EPR pairs to interact with the identification token. Then the authentication is accomplished by a complete Bell state measurement. This scheme is proved to be secure. If no errors and eavesdroppers exist in the transmission, the identification token is unchanged after the authentication. So it can be reused.

ENTANGLEMENT DYNAMICS OF TRANSFERRING BELL STATES IN SPIN CHAINS

2010 ◽  
Vol 24 (17) ◽  
pp. 3341-3349 ◽  
Author(s):  
JIE REN ◽  
SHIQUN ZHU
Keyword(s):  
Quantum Wire ◽  
Bell State ◽  
Spin Chains ◽  
Bell States ◽  
Entanglement Dynamics ◽  
State Formula ◽  
Better Than

A teleportation scheme between two arbitrary locations is introduced. The locations only need to establish a quantum wire to a super-location. The super-location can create and transfer Bell states by two unmodulated and coupled spin chains or by two engineered spin chains. The entanglement of transferring the Bell state of [Formula: see text] is better than that of transferring state [Formula: see text].

scholarly journals PENGARUH FILLER ABU AMPAS TEBU (AAT) DENGAN BAHAN PENGIKAT ASPAL PEN 60/70 PADA CAMPURAN LASTON AC-WC

2018 ◽  
Vol 1 (4) ◽  
pp. 69-78
Author(s):  
Febrina Dian Kurniasari ◽  
Sofyan M. Saleh ◽  
Sugiarto Sugiarto
Keyword(s):  
Mixed Layer ◽  
Asphalt Mixture ◽  
Waste Materials ◽  
Road Pavement ◽  
Alternative Materials ◽  
Characteristic Values ◽  
Low Strength ◽  
Strength And Durability ◽  
Very High

Cause of occurrence damage and decrease of road pavement strength is low strength and durability in a mixed layer (AC-WC). To overcome this problem, it is necessary to improve the quality of  road pavement in aggregate, filler, and asphalt composition. Filler serves to isolate the cavities between the aggregate particles so as to increase the density of the mixture. In general, the filler of stone ash has been used. However, it is important to find for other alternative materials which utilizing waste materials such as dregs of bagasse. The content of silica (SiO2) in ashes of bagasse is very high, 42.47%, thus it is expected to improve the quality of asphalt mixture. This study aims to determine the effect of using ashes of bagasse over the characteristics of mixed laston layer (AC-WC) with the addition of bagasse ash from 0%, 25%, 50%, 75% and 100%. This study refers to the 2010 Bina Marga Specification Revision 3 Year 2014. The results show that the addition of ash of bagasse has increased stability value. In general, the characteristic values that meet the requirements are found in the composition of 50% filler ash of bagasse asphalt at 5.87%, VIM value of 4.61%, VMA 18.41%, flow 3.17 mm and stability is 1344 , 04 kg.

scholarly journals Periodicity and perfect state transfer in quantum walks on variants of cycles

2014 ◽  
Vol 14 (5&6) ◽  
pp. 417-438
Author(s):  
Katharine E. Barr ◽  
Tim J. Proctor ◽  
Daniel Allen ◽  
Viv M. Kendon
Keyword(s):  
Discrete Time ◽  
Initial Conditions ◽  
Quantum Walks ◽  
High Fidelity ◽  
Perfect State ◽  
Initial State ◽  
State Transfer ◽  
Time Quantum ◽  
Perfect State Transfer ◽  
Very High

We systematically investigated perfect state transfer between antipodal nodes of discrete time quantum walks on variants of the cycles $C_4$, $C_6$ and $C_8$ for three choices of coin operator. Perfect state transfer was found, in general, to be very rare, only being preserved for a very small number of ways of modifying the cycles. We observed that some of our useful modifications of $C_4$ could be generalised to an arbitrary number of nodes, and present three families of graphs which admit quantum walks with interesting dynamics either in the continuous time walk, or in the discrete time walk for appropriate selections of coin and initial conditions. These dynamics are either periodicity, perfect state transfer, or very high fidelity state transfer. These families are modifications of families known not to exhibit periodicity or perfect state transfer in general. The robustness of the dynamics is tested by varying the initial state, interpolating between structures and by adding decoherence.

Quantum-entanglement storage and extraction in quantum network node

2018 ◽  
Vol 16 (01) ◽  
pp. 1850009 ◽  
Author(s):  
ZhuoYu Shan ◽  
Yong Zhang
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Entanglement ◽  
Information Technologies ◽  
Quantum Information Processing ◽  
Bell State ◽  
Nitrogen Vacancy ◽  
Quantum Network ◽  
Nuclear Spins ◽  
Nv Centers

Quantum computing and quantum communication have become the most popular research topic. Nitrogen-vacancy (NV) centers in diamond have been shown the great advantage of implementing quantum information processing. The generation of entanglement between NV centers represents a fundamental prerequisite for all quantum information technologies. In this paper, we propose a scheme to realize the high-fidelity storage and extraction of quantum entanglement information based on the NV centers at room temperature. We store the entangled information of a pair of entangled photons in the Bell state into the nuclear spins of two NV centers, which can make these two NV centers entangled. And then we illuminate how to extract the entangled information from NV centers to prepare on-demand entangled states for optical quantum information processing. The strategy of engineering entanglement demonstrated here maybe pave the way towards a NV center-based quantum network.

scholarly journals Parallel single-shot measurement and coherent control of solid-state spins below the diffraction limit

Science ◽  
2020 ◽  
Vol 370 (6516) ◽  
pp. 592-595
Author(s):  
Songtao Chen ◽  
Mouktik Raha ◽  
Christopher M. Phenicie ◽  
Salim Ourari ◽  
Jeff D. Thompson
Keyword(s):  
Solid State ◽  
Coherent Control ◽  
Quantum Information Processing ◽  
High Fidelity ◽  
Single Shot ◽  
Frequency Domain Multiplexing ◽  
Spin Interactions ◽  
Quantum Science ◽  
Logic Operations ◽  
State Spin

Solid-state spin defects are a promising platform for quantum science and technology. The realization of larger-scale quantum systems with solid-state defects will require high-fidelity control over multiple defects with nanoscale separations, with strong spin-spin interactions for multi-qubit logic operations and the creation of entangled states. We demonstrate an optical frequency-domain multiplexing technique, allowing high-fidelity initialization and single-shot spin measurement of six rare-earth (Er3+) ions, within the subwavelength volume of a single, silicon photonic crystal cavity. We also demonstrate subwavelength control over coherent spin rotations by using an optical AC Stark shift. Our approach may be scaled to large numbers of ions with arbitrarily small separation and is a step toward realizing strongly interacting atomic defect ensembles with applications to quantum information processing and fundamental studies of many-body dynamics.

scholarly journals Design of Neutron Microscopes Equipped with Wolter Mirror Condenser and Objective Optics for High-Fidelity Imaging and Beam Transport

2020 ◽  
Vol 6 (10) ◽  
pp. 100 ◽  
Author(s):  
Muhammad Abir ◽  
Daniel S. Hussey ◽  
Boris Khaykovich
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Neutron Imaging ◽  
High Fidelity ◽  
Signal Rate ◽  
Pinhole Imaging ◽  
Standard Neutron ◽  
Resolution Imaging ◽  
Very High ◽  
Better Than

We present and compare the designs of three types of neutron microscopes for high-resolution neutron imaging. Like optical microscopes, and unlike standard neutron imaging instruments, these microscopes have both condenser and image-forming objective optics. The optics are glancing-incidence axisymmetric mirrors and therefore suitable for polychromatic neutron beams. The mirrors are designed to provide a magnification of 10 to achieve a spatial resolution of better than 10 μm. The resolution of the microscopes is determined by the mirrors rather than by the L/Dratio as in conventional pinhole imaging, leading to possible dramatic improvements in the signal rate. We predict the increase in the signal rate by at least two orders of magnitude for very high-resolution imaging, which is always flux limited. Furthermore, in contrast to pinhole imaging, in the microscope, the samples are placed far from the detector to allow for a bulky sample environment without sacrificing spatial resolution.

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