IMPROVED MEAN-FIELD TRANSFER MATRIX MODEL FOR HYPERCUBIC ISING SYSTEMS

2012 ◽  
Vol 26 (17) ◽  
pp. 1250111 ◽  
Author(s):  
TUNCER KAYA
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Transfer Matrix ◽  
Coupling Strength ◽  
Mean Field ◽  
Field Method ◽  
Critical Coupling ◽  
Average Magnetization ◽  
Self Consistent ◽  
Ising Systems

A mean-field method for Ising systems is introduced generalizing the reduced transfer matrix method introduced by Kaya and Arık. The important assumption of the method is that the neighboring spins of a central spin can be replaced by the average magnetization 〈σ〉 of the system. The approximation is same as the previously introduced method. However, the derivative of average magnetization with respect to external magnetic field is defined without further approximation. In addition, the previously introduced model is extended to all hypercubic lattices. The critical coupling strength Kc for hypercubic lattices is evaluated self-consistently. Obviously, this assumption leads to some significant deviation from the exact treatment. However, the model introduced here is an improvement on most self-consistent mean-field-type approximations.

REDUCED TRANSFER MATRIX APPROACH FOR ISING MODEL

2011 ◽  
Vol 25 (21) ◽  
pp. 2895-2903 ◽  
Author(s):  
TUNCER KAYA ◽  
MURAT ARIK
Keyword(s):  
Transfer Matrix ◽  
Coupling Strength ◽  
Spontaneous Magnetization ◽  
Mean Field Theory ◽  
Mean Field ◽  
Three Dimensional ◽  
Critical Coupling ◽  
Transfer Matrix Approach ◽  
The Mean ◽  
2D And 3D

In this work, we present a simple approximate transfer matrix method for 2D and 3D Ising ferromagnet to calculate spontaneous magnetization of the system. The critical coupling strength Kc of 2D and 3D Ising models in reduced transfer matrix approximation is obtained quite accurately by simple improvements over the mean field theory. The important physical effect we include is the some of the fluctuations effects of the systems directly with help of this method. We predict from the spontaneous magnetization curve that the critical coupling strength Kc=J/kBT = 0.401 and 0.245 for two-dimensional (2D) and three-dimensional (3D) systems, respectively.

Teleportation of the entangled state of two superconducting qubits

2021 ◽  
Author(s):  
S. Salimian ◽  
Mohammad K. Tavassoly ◽  
N. Sehati
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Coupling Strength ◽  
Success Probability ◽  
Decay Rates ◽  
Ghz State ◽  
Superconducting Qubits ◽  
Entangled State ◽  
Efficient Scheme ◽  
Two Level Systems

Abstract An efficient scheme is proposed to teleport an entangled state of two superconducting (SC) qubits from Alice's to Bob's lab. This type of two-level systems has recently attracted a lot of attention due to the possible tunability of the coupling strength of the qubits with each other. To achieve the purpose, we first generate the GHZ state as the necessary teleportation channel. Then, appropriate interactions are performed in two processes between two of the five qubits, each with a certain frequency modulative external magnetic field which is applied on specific one of the qubits. Next, via applying proper gates and measurements in each lab, we observe that the teleportation can be successfully performed with maximum possible values of fidelity and success probability. At last, to make the protocol close to reality, decay rates of SC qubits are also taken into account, showing that our protocol still works well, satisfactorily.

scholarly journals Mean-field Theory of the Meissner Effect in Bulk Revisited

2020 ◽  
Author(s):  
Ladislaus Banyai
Keyword(s):  
Magnetic Field ◽  
Mean Field Theory ◽  
Mean Field ◽  
Meissner Effect ◽  
Transverse Current ◽  
Self Consistent ◽  
Full Compensation ◽  
London Equation ◽  
Current Interaction ◽  
Constant External Magnetic Field

We show that the implementation of the 1/c² transverse current-current interaction between electrons into the standard self-consistent electron BCS model in bulk under thermal equilibrium ensures in the stable superconductive phase the full compensation of a constant external magnetic field by the internal magnetic field created by the electrons i.e. one has an ideal diamagnet. However, no proof of the phenomenological London equation emerges within the bulk approach.

scholarly journals Peningkatan Kedalaman Penetrasi Las Stainless Steel 304 dengan Medan Magnet Eksternal pada Pengelasan Autogenous Tungsten Inert Gas Welding

2021 ◽  
Vol 12 (1) ◽  
pp. 87
Author(s):  
Haikal Haikal ◽  
Moch. Chamim ◽  
Deni Andriyansyah ◽  
Apri Wiyono ◽  
Ario Sunar Baskoro ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Welding Speed ◽  
Weld Line ◽  
Welding Process ◽  
Welding Current ◽  
Field Method ◽  
Inert Gas ◽  
Welding Parameters ◽  
Bead Width

<p class="Abstract">In this study, research on the use of the External Magnetic Field method – Tungsten Inert Gas was done to determine the effect of welding arc compression on the quality of <em>AISI 304 </em>thin plate weld. The welding process was performed using autogenous welds. In this study, an external magnetic field was generated by placing a magnetic solenoid around the <em>TIG</em> welding torch. Enabling this electromagnetic field is done dynamically using a microcontroller. Welding parameters used are welding current <em>100; 105; 110 A</em> and welding speed <em>1.6; 1.8; 2.05 mm/s</em>. The results of this study showed that <em>EMF-TIG</em> welding can produce a more uniform bead width along the weld line with a standard deviation of 0.08 compared with conventional <em>TIG </em>welding of <em>0.12</em>. Increased welding speed of  <em>2.05 mm/s</em> causes no effect on the addition of an external magnetic field to the width of the weld bead. The current parameters are <em>105 A </em>with a speed of <em>1.6; 1.8; 2.05 mm/s</em> resulted in compression of the top bead width by <em>0.87; 0.61; 0.1 mm</em>. The welding parameters with a current of 105 A and welding speed of <em>1.6 mm/s</em> have a larger upper bead compression effect of <em>0.84 mm</em> compared to <em>110 A</em> currents of <em>0.38 mm</em>. Moreover, the <em>D/W</em> ratio obtained under an external magnetic field was higher than without magnetic.</p>

Self-consistent model of an inductive RF plasma source in an external magnetic field

2004 ◽  
Vol 30 (5) ◽  
pp. 398-412 ◽  
Author(s):  
A. F. Aleksandrov ◽  
G. É. Bugrov ◽  
K. V. Vavilin ◽  
I. F. Kerimova ◽  
S. G. Kondranin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Plasma Source ◽  
Rf Plasma ◽  
Consistent Model ◽  
Self Consistent

scholarly journals Mean-field BCS theory of the Meissner effect in bulk revisited

2021 ◽  
Vol 94 (1) ◽  
Author(s):  
Ladislaus Alexander Bányai
Keyword(s):  
Magnetic Field ◽  
Thermal Equilibrium ◽  
Mean Field ◽  
Meissner Effect ◽  
Bcs Theory ◽  
Transverse Current ◽  
Self Consistent ◽  
Full Compensation ◽  
Current Interaction ◽  
Constant External Magnetic Field

Abstract We show that the implementation of the $$1/ c^2 $$ 1 / c 2 transverse current–current interaction between electrons resulting from the non-relativistic QED into the standard self-consistent electron BCS model in bulk under thermal equilibrium in the stable superconductive phase ensures the full compensation of a constant external magnetic field by the internal magnetic field created by the electrons, i.e. one has an ideal diamagnet. GraphicAbstract

scholarly journals Effect of external magnetic field on the co-existence of superconductivity and antiferromagnetism in rare earth nickel borocarbides (RNi2B2C)

2016 ◽  
Vol 30 (08) ◽  
pp. 1650044
Author(s):  
Salila Das ◽  
Prakash Chandra Padhi
Keyword(s):  
Magnetic Field ◽  
Rare Earth ◽  
External Magnetic Field ◽  
Energy Gap ◽  
Density Wave ◽  
Spin Density Wave ◽  
Mean Field ◽  
Antiferromagnetic Order ◽  
Superconducting Energy Gap ◽  
Nickel Borocarbides

In this paper, we have studied the effect of external magnetic field in the co-existing phase of superconducting and antiferromagnetism (AFM) of rare earth nickel borocarbides. The AFM in these systems might have originated due to both localized “f” electrons as well as itinerant electrons which are responsible for conduction. On the other hand, superconductivity (SC) is due to spin density wave, arising out of Fermi surface instability. The AFM order is mostly influenced by hybridization of the “f” electron with the conduction electron. Here, we have obtained the dependence of superconducting energy gap as well as staggered magnetic field on temperature T and energy [Formula: see text] in a framework based on mean field Hamiltonian using double time electron Green’s function. We have shown in our calculation the effect of external magnetic field on superconducting and antiferromagnetic order parameters for [Formula: see text] in the presence of hybridization. The ratio of the calculated effective gap and [Formula: see text] is close to BCS value which agrees quite well with experimental results.

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