Controlling measurement-induced nonlocality in the Heisenberg XX model by three-spin interactions

2018 ◽  
Vol 32 (01) ◽  
pp. 1750268 ◽  
Author(s):  
Yu-Xia Xie ◽  
Yu-Hang Sun ◽  
Zhao Li
Keyword(s):  
Transverse Field ◽  
Spin Interaction ◽  
Maximum Enhancement ◽  
System Parameters ◽  
Interaction Terms ◽  
Spin Interactions ◽  
Xx Model ◽  
Heisenberg Xx Model ◽  
Thermal States

We investigate the well-defined measures of measurement-induced nonlocality (MIN) for thermal states of the transverse field XX model, with the addition of three-spin interaction terms being introduced. The results showed that the MINs are very sensitive to system parameters of the chain. The three-spin interactions can serve as flexible parameters for enhancing MINs of the boundary spins, and the maximum enhancement achievable by varying strengths of the three-spin interactions are different for the chain with different number of spins.

scholarly journals Symmetry mediated tunable molecular magnetism on a 2D material

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yuqi Wang ◽  
Soroush Arabi ◽  
Klaus Kern ◽  
Markus Ternes
Keyword(s):  
Single Molecule ◽  
Twist Angle ◽  
Layered Material ◽  
Spin Interaction ◽  
Transition Metal Dichalcogenide ◽  
Nanoscale Structures ◽  
Reduced Dimensions ◽  
Spin Interactions ◽  
Metal Organic ◽  
Probe Microscope

AbstractSymmetries in nanoscale structures can be decisive for their structural, electronic, and magnetic properties, particularly in systems with reduced dimensions. Here we show that the symmetries of a flat metal-organic molecule adsorbed on a transition metal dichalcogenide, a 2-dimensional layered material, have a dramatic effect on the total spin and the intramolecular spin-spin interactions. Using a scanning probe microscope, we find two different molecular spin states by modifying the symmetry of the molecules via the twist angle to the substrate. Additionally, we observe significant non-collinear Dzyaloshinskii–Moriya interaction between two electron spins on the molecule induced by the spin-orbit coupling of the van der Waals coupled layered material with broken inversion symmetry. Our work opens a path for modifying the spin by exploiting symmetries and for studying the nature of surface-induced non-collinear spin-spin interaction within a single molecule which might allow the realization of more complex topological spin structures.

scholarly journals Optimizing a quantum reservoir computer for time series prediction

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Aki Kutvonen ◽  
Keisuke Fujii ◽  
Takahiro Sagawa
Keyword(s):  
Time Series ◽  
Language Processing ◽  
Quantum Dynamics ◽  
Time Series Prediction ◽  
Transverse Field ◽  
Memory Capacity ◽  
Great Promise ◽  
Real World Data ◽  
Spin Interactions ◽  
Transverse Field Ising Model

Abstract Quantum computing and neural networks show great promise for the future of information processing. In this paper we study a quantum reservoir computer (QRC), a framework harnessing quantum dynamics and designed for fast and efficient solving of temporal machine learning tasks such as speech recognition, time series prediction and natural language processing. Specifically, we study memory capacity and accuracy of a quantum reservoir computer based on the fully connected transverse field Ising model by investigating different forms of inter-spin interactions and computing timescales. We show that variation in inter-spin interactions leads to a better memory capacity in general, by engineering the type of interactions the capacity can be greatly enhanced and there exists an optimal timescale at which the capacity is maximized. To connect computational capabilities to physical properties of the underlaying system, we also study the out-of-time-ordered correlator and find that its faster decay implies a more accurate memory. Furthermore, as an example application on real world data, we use QRC to predict stock values.

scholarly journals Michel Borghini as a Mentor and Father of the Theory of Polarization in Polarized Targets

2016 ◽  
Vol 40 ◽  
pp. 1660116
Author(s):  
Wim de Boer
Keyword(s):  
Amorphous Materials ◽  
High Energy Physics ◽  
High Energy ◽  
Spin Interaction ◽  
Dynamic Polarization ◽  
Spin Interactions ◽  
High Dynamic ◽  
Polarized Targets ◽  
First Time ◽  
Energy Physics

This paper is a contribution to the memorial session for Michel Borghini at the Spin 2014 conference in Bejing, honoring his pivotal role for the development of polarized targets in high energy physics. Borghini proposed for the first time the correct mechanism for dynamic polarization in polarized targets using organic materials doped with free radicals. In these amorphous materials the spin levels are broadened by spin-spin interactions and g-factor anisotropy, which allows a high dynamic polarization of nuclei by cooling of the spin-spin interaction reservoir. In this contribution I summarize the experimental evidence for this mechanism. These pertinent experiments were done at CERN in the years 1971 - 1974, when I was a graduate student under the guidance of Michel Borghini. I finish by shortly describing how Borghini’s spin temperature theory is now applied in cancer therapy.

Thermal Entanglement Entropy Signature of Spin-Peierls Transition in Dimerized Isotropic XY Chain with Multi-Spin Interactions

2014 ◽  
Vol 1021 ◽  
pp. 46-51
Author(s):  
Hai Lin Huang ◽  
Lin Jie Ding ◽  
Zhao Yu Sun
Keyword(s):  
Green's Function ◽  
Finite Temperature ◽  
Function Theory ◽  
Critical Phenomenon ◽  
Entanglement Entropy ◽  
Spin Interaction ◽  
Thermal Entanglement ◽  
Spin Interactions ◽  
Wigner Transformation ◽  
Peierls Transition

The finite-temperature entanglement entropy for an alternating spin-1/2 chain with multi-spin interactions is investigated by means of Green’s function theory combined with Jordan-Wigner transformation, to identify the spin-Peierls (SP) transition. It is found that the two-site thermal entanglement entropy is a useful tool to characterize theSPtransition. In addition, the competition between multi-spin interaction and Peierls-dimerization plays a central role in the critical phenomenon of the system.

Spin Spin Interactions in Polynuclear Nickel(II) Complexes. a Magnetic and Structural Study of Binuclear Nickel(II) Complexes of Enolic 1,3,5-Triketonates

1986 ◽  
Vol 39 (8) ◽  
pp. 1249 ◽  
Author(s):  
PDW Boyd ◽  
KS Lee ◽  
M Zvagulis
Keyword(s):  
Marked Decrease ◽  
Nickel Complexes ◽  
Spin Coupling ◽  
Spin Interaction ◽  
Binuclear Copper ◽  
X Ray ◽  
Spin Interactions ◽  
Spin Spin Coupling ◽  
Antiferromagnetic Spin ◽  
Oxygen Bond

The bulk magnetic susceptibilities of the binuclear nickel(II) complexes of the 1,3,5-triketonates from diethyl (2-oxocyclopentane- 1,3-diyl) bisglyoxylate (H2ecg) (1) and diethyl 2,4,6-trioxoheptanedioate (H2decg) (2) have been measured over the temperature range 6-300 K. Antiferromagnetic spin-spin coupling is observed in each case with Neel temperatures in the range 45-65 K. The X-ray crystal structure of [Ni( ecg )( py )2]2.( py ) has been solved. The complex crystallizes with one pyridine of solvation in the space group Pī [a 10.507(1), b 13.384(1), c 9.992(1) Ǻ, α 103.004(9), β 115.867(9), β 86.857(10)°, Z = 1]. The molecule is binuclear with two coplanar triketonate dianions bridging the two six-coordinate nickel atoms through a di-μ-oxo linkage [Ni-Ob-Ni angle 102.0(1)°]. Two pyridine molecules and four triketonate oxygen atoms are bound to each nickel atoms. Magnetostructural correlations are presented in comparison with binuclear copper(II) 1,3,5-triketonates. The marked decrease in spin-spin interaction in the nickel complexes is attributed to increasing metal-bridging oxygen bond lengths that decrease the efficacy of the σ antiferromagnetic pathway xy||Ob||xy and contributions from the ferromagnetic xy||Ob||z2 pathway.

DAMAGE SPREADING ON THE HOMO- AND HETERO-CELL LATTICES WITH COMPETING GLAUBER AND KAWASAKI DYNAMICS

2008 ◽  
Vol 22 (16) ◽  
pp. 2545-2555 ◽  
Author(s):  
Z. Z. GUO ◽  
XIAO-WEI WU
Keyword(s):  
Long Range ◽  
Nearest Neighbor ◽  
Hexagonal Lattice ◽  
Interaction Strength ◽  
Spin Interaction ◽  
Kawasaki Dynamics ◽  
Range Interaction ◽  
Damage Spreading ◽  
Spin Interactions ◽  
Long Range Interaction

The damage spreading of the Ising model on the homo- and hetero-cell lattices (here the topological hexagonal lattice and the 4–8 lattice) with competing Glauber (G-) and Kawasaki (K-) dynamics is studied and the results are compared. For the homo-cell lattice, we pay attention to the pure K-dynamics or the cases in which the K-dynamics is dominant. We get four main conclusions related to the K-dynamics through our calculations: (1) the damage always spreads as long as Kawasaki dynamics is dominant during the competition of two dynamics; (2) the relation for the saturation damage, 〈s〉∞ = 0.5, holds for K-dynamics whatever the updating rules are; (3) 〈s〉∞ = 0.5 is independent of the structures of the system; (4) the DS process under pure K-dynamics converges very slowly, especially for T = 0 K-dynamics. For the hetero-cell lattice, we are interested in the long-range interaction between spins and the different interaction strength for the spins in the hetero-cells. To include the long-range spin interaction, we consider the spin interactions up to next-nearest neighbors. It is shown that the inclusion of the next-nearest-neighbor interaction enhances the transition temperature greatly. The explanation and discussion for the results are presented.

Protocols for three-party quantum teleportation using Heisenberg XX model

2007 ◽  
Vol 34 (2) ◽  
pp. 187-196 ◽  
Author(s):  
Kunsang Lee ◽  
Yeonjoo Choi ◽  
Younghun Kwon
Keyword(s):  
Quantum Teleportation ◽  
Xx Model ◽  
Heisenberg Xx Model
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