scholarly journals Theory of generalized Josephson effects

2020 ◽  
Vol 2020 (7) ◽  
Author(s):  
Aron J Beekman
Keyword(s):  
Josephson Effect ◽  
Chemical Potential ◽  
Weak Link ◽  
Energy Difference ◽  
Separation Distance ◽  
Broken Symmetry ◽  
Josephson Effects ◽  
Continuous Symmetry ◽  
Two Systems ◽  
Noether Current

Abstract The DC Josephson effect is the flow of supercurrent across a weak link between two superconductors with different values of their order parameters, the phase. We formulate this notion for any kind of spontaneous continuous symmetry breaking. The quantity that flows between the two systems is the zero-wavenumber Noether current associated with the broken symmetry. The AC Josephson effect is the oscillation of current due to the energy difference between the two systems caused by an imposed asymmetric chemical potential of Noether charge. As an example of novel physics, a Josephson effect is predicted between two crystalline solids, potentially measurable as a force periodic in the separation distance.

scholarly journals Edge channels of broken-symmetry quantum Hall states in graphene visualized by atomic force microscopy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sungmin Kim ◽  
Johannes Schwenk ◽  
Daniel Walkup ◽  
Yihang Zeng ◽  
Fereshte Ghahari ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Potential ◽  
Quantum Hall ◽  
Broken Symmetry ◽  
Topological Order ◽  
Edge States ◽  
Force Microscopy ◽  
Atomic Force ◽  
Intimate Relation ◽  
Boundary Measurements

AbstractThe quantum Hall (QH) effect, a topologically non-trivial quantum phase, expanded the concept of topological order in physics bringing into focus the intimate relation between the “bulk” topology and the edge states. The QH effect in graphene is distinguished by its four-fold degenerate zero energy Landau level (zLL), where the symmetry is broken by electron interactions on top of lattice-scale potentials. However, the broken-symmetry edge states have eluded spatial measurements. In this article, we spatially map the quantum Hall broken-symmetry edge states comprising the graphene zLL at integer filling factors of $${{\nu }}={{0}},\pm {{1}}$$ ν = 0 , ± 1 across the quantum Hall edge boundary using high-resolution atomic force microscopy (AFM) and show a gapped ground state proceeding from the bulk through to the QH edge boundary. Measurements of the chemical potential resolve the energies of the four-fold degenerate zLL as a function of magnetic field and show the interplay of the moiré superlattice potential of the graphene/boron nitride system and spin/valley symmetry-breaking effects in large magnetic fields.

Non-Linear Optical Properties and Global Reactivity Descriptors by ab initio Hartree-Fock (H.F.) Calculations of Simple Coumarins

2021 ◽  
Vol 9 (2) ◽  
pp. 7-20
Author(s):  
P. Sumalatha ◽  
◽  
N. Muralikrishna ◽  
K.V. Padmavathi ◽  
M. Subbarao ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Potential ◽  
Molecular Descriptors ◽  
Resistance To Change ◽  
Energy Difference ◽  
Polarizable Continuum Model ◽  
Basis Set ◽  
Optical Parameters ◽  
Reactivity Descriptors ◽  
Molecular Hyperpolarizability

In this present analysis, the measurement of optimized molecular structure and molecular hyperpolarizability (βtotal) of simple coumarin molecules were investigated using the HF method at 6-311G basis set level Gaussian09W. The measured nonlinear optical parameters (NLO); polarizability (α), the anisotropy of the polarizability (Δα), and first-order molecular hyperpolarizability (βtotal) of the studied coumarins indicate promising optical properties. The energy difference between HOMO and LUMO helped determine the molecular descriptors; global hardness (η), softness (σ) electronegativity (χ) Chemical potential (μ), and electrophilicity index (ω) in gas and different solvents. The molecular hyperpolarizability (βtotal) and descriptors that have been calculated in the solvent medium were taken into consideration through the Polarizable Continuum Model (PCM), This study shows the high static hyperpolarizability exhibited by HNR, FXT, and CNT and offers the potential the materials may have for NLO devices. The molecular descriptors, hardness, and chemical potential values are high for CNT and UCAcompared to other studied coumarins. This suggested that CNT and CA have the most significant chemical potential resistance to change the number of electrons among the other molecules.

scholarly journals Josephson effect in a weak link between borocarbides

2005 ◽  
Vol 31 (2) ◽  
pp. 137-138 ◽  
Author(s):  
Yu. A. Kolesnichenko ◽  
S. N. Shevchenko
Keyword(s):  
Josephson Effect ◽  
Weak Link

Josephson effect in superconductor/ferromagnet structures with a complex weak-link region

2010 ◽  
Vol 81 (21) ◽  
Author(s):  
T. Yu. Karminskaya ◽  
A. A. Golubov ◽  
M. Yu. Kupriyanov ◽  
A. S. Sidorenko
Keyword(s):  
Josephson Effect ◽  
Weak Link

scholarly journals Stationary Josephson effect in a weak link between nonunitary triplet superconductors

2005 ◽  
Vol 31 (6) ◽  
pp. 481-485 ◽  
Author(s):  
G. Rashedi ◽  
Yu. A. Kolesnichenko
Keyword(s):  
Josephson Effect ◽  
Weak Link

Josephson effects in one junction with one s-wave superconductor and two topological superconductors

2019 ◽  
Vol 33 (03) ◽  
pp. 1950019 ◽  
Author(s):  
Li-Hui Jin ◽  
Xiao-Qi Wang ◽  
Guang-Yu Yi
Keyword(s):  
Quantum Dot ◽  
Phase Difference ◽  
Josephson Effect ◽  
Superconducting Phase ◽  
Josephson Effects ◽  
S Wave ◽  
Topological Superconductors

We present an analysis of Josephson effects in one quantum-dot-embedded junction with one s-wave superconductor (SC) and two topological superconductors (TSs). It is found that when superconducting phase difference is applied between the two TSs, the dot-SC coupling can efficiently modulate the fractional Josephson effect, including the changes of the supercurrent oscillation direction and period. Even though the polarization directions of the TSs are opposite, the dot-SC coupling enables to drive the fractional Josephson effect between the TSs. Next, as the superconducting phase difference is introduced between the TSs and SC, only the normal Josephson effect takes place.

scholarly journals Transition from phase slips to the Josephson effect in a superfluid 4He weak link

2005 ◽  
Vol 2 (1) ◽  
pp. 23-26 ◽  
Author(s):  
E. Hoskinson ◽  
Y. Sato ◽  
I. Hahn ◽  
R. E. Packard
Keyword(s):  
Josephson Effect ◽  
Weak Link ◽  
Superfluid 4He ◽  
Phase Slips

scholarly journals Symmetric Graphene Dielectric Nanowaveguides as Ultra-Compact Photonic Structures

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1281
Author(s):  
Da Teng ◽  
Yuncheng Wang ◽  
Tianzi Xu ◽  
Huayu Wang ◽  
Qinqin Shao ◽  
...  
Keyword(s):  
Figure Of Merit ◽  
Chemical Potential ◽  
Separation Distance ◽  
Plasmon Mode ◽  
Structure Parameters ◽  
The Finite Element Method ◽  
Mid Infrared ◽  
Modal Properties ◽  
Mode Field ◽  
Field Area

A symmetric graphene plasmon waveguide (SGPWG) is proposed here to achieve excellent subwavelength waveguiding performance of mid-infrared waves. The modal properties of the fundamental graphene plasmon mode are investigated by use of the finite element method. Due to the naturally rounded tips, the plasmon mode in SGPWG could achieve a normalized mode field area of ~10−5 (or less) and a figure of merit over 400 by tuning the key geometric structure parameters and the chemical potential of graphene. In addition, results show that the modal performance of SGPWG seems to improve over its circular counterparts. Besides the modal properties, crosstalk analysis indicates that the proposed waveguide exhibits extremely low crosstalk, even at a separation distance of 64 nm. Due to these excellent characteristics, the proposed waveguide has promising applications in ultra-compact integrated photonic components and other intriguing nanoscale devices.

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