scholarly journals Possible Alterations of Local Gravitational Field Inside a Superconductor

Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 193 ◽  
Author(s):  
Giovanni Alberto Ummarino ◽  
Antonio Gallerati
Keyword(s):  
Gravitational Field ◽  
Landau Theory ◽  
Time Dependent ◽  
Qualitative Comparison ◽  
Ginzburg Landau ◽  
High Tc ◽  
Gravitational Fields ◽  
Favorable Conditions

We calculate the possible interaction between a superconductor and the static Earth’s gravitational fields, making use of the gravito-Maxwell formalism combined with the time-dependent Ginzburg–Landau theory. We try to estimate which are the most favorable conditions to enhance the effect, optimizing the superconductor parameters characterizing the chosen sample. We also give a qualitative comparison of the behavior of high–Tc and classical low–Tc superconductors with respect to the gravity/superfluid interplay.

scholarly journals Effect of Higher Landau Levels on the Transverse Thermoelectric Conductivity in High-\(T_{c}\) Superconductors

2017 ◽  
Vol 26 (3) ◽  
pp. 279
Author(s):  
Bui Duc Tinh
Keyword(s):  
Gaussian Approximation ◽  
Landau Theory ◽  
Landau Levels ◽  
Time Dependent ◽  
Dimensional Model ◽  
Ginzburg Landau ◽  
High Tc ◽  
High Tc Superconductor ◽  
Self Consistent ◽  
Good Agreement

We investigate effect of higher Ladau levels on the transverse thermoelectricconductivity \(\alpha_{xy}\), describing the Nernst effect in high-\(T_c\) superconductors, by using the time-dependent Ginzburg-Landau theory in two dimensional model withthermal noise. The transverse thermoelectric conductivity is calculated inthe self-consistent Gaussian approximation. Our results indicate that thehigher Landau levels are, the less these levels contribute to the transversethermoelectric conductivity. Our results are in good agreement with experimental dataon high-Tc superconductor.

scholarly journals Solution Theory of Ginzburg-Landau Theory on BCS-BEC Crossover

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Shuhong Chen ◽  
Zhong Tan
Keyword(s):  
Global Existence ◽  
Strong Solution ◽  
Sobolev Spaces ◽  
Landau Theory ◽  
Strong Solutions ◽  
Time Dependent ◽  
Solution Theory ◽  
Ginzburg Landau ◽  
Spatial Dimensions

We establish strong solution theory of time-dependent Ginzburg-Landau (TDGL) systems on BCS-BEC crossover. By the properties of Besov, Sobolev spaces, and Fourier functions and the method of bootstrapping argument, we deduce that the global existence of strong solutions to time-dependent Ginzburg-Landau systems on BCS-BEC crossover in various spatial dimensions.

Dynamics of vortex–antivortex creation and annihilation in current-driven mesoscopic superconducting squares

2015 ◽  
Vol 29 (35n36) ◽  
pp. 1550247
Author(s):  
Xiao-Meng Liang ◽  
Guo-Qiao Zha
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Landau Theory ◽  
Symmetric Case ◽  
Time Dependent ◽  
Dynamical Process ◽  
Applied Bias ◽  
Ginzburg Landau ◽  
Dc Drive ◽  
Vortex Velocity

In this paper, based on the time-dependent Ginzburg–Landau theory, we study the dynamics of vortex–antivortex (V–Av) pairs in a mesoscopic superconducting square with a small hole under applied bias currents. For the sample with a centered hole, a V–Av pair can nucleate at the hole edges and moves in opposite directions perpendicular to applied constant DC drive. The influence of the external magnetic field on the (anti)vortex velocity and the lifetime of V–Av pairs is mainly investigated. Different modes in the dynamical process of the V–Av collision and annihilation are identified. Moreover, in the case when the hole is displaced from the center of the square, the V–Av dynamics behaves quite differently from the symmetric case due to the shift of the V–Av creation point.

Theories of High Tc Superconductors

1987 ◽  
Vol 99 ◽  
Author(s):  
John Bardeen
Keyword(s):  
Low Temperatures ◽  
Landau Theory ◽  
3D Models ◽  
Oxide Superconductors ◽  
High Tc Superconductors ◽  
Pairing Interaction ◽  
Ginzburg Landau ◽  
High Tc ◽  
Wide Range ◽  
High Transition

ABSTRACTMany theories have been given to account for the high transition temperatures in the oxide superconductors. While most are based on pairing, they differ as to the origin of the attractive interaction that gives rise to the pairs and whether the pairing is weak or strong. If weak(λ < ∼ 0.5), the energy range of the pairing interaction must be wider than is consistent with one mediated solely by phonons. With measurements on single crystals becoming available, giving data covering a wide range of frequencies and temperatures, it is possible to narrow down the possible options. The data show that anisotropie 3D models are required. Observed isotope shifts indicate that phonons must play a role, but additional mechanisms are likely necessary to account for the high T's. Thermal, magnetic and transport data are consistent with anisotropie Ginzburg-Landau theory near T, with expected departures at low temperatures.

scholarly journals Multi-mode excitation drives disorder during the ultrafast melting of a C4-symmetry-broken phase

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Daniel Perez-Salinas ◽  
Allan S. Johnson ◽  
Dharmalingam Prabhakaran ◽  
Simon Wall
Keyword(s):  
Phase Transitions ◽  
Order Parameter ◽  
Landau Theory ◽  
Mean Field ◽  
Atomic Scale ◽  
Time Dependent ◽  
Ginzburg Landau ◽  
Mode Excitation ◽  
The Mean ◽  
Multi Mode

AbstractSpontaneous C4-symmetry breaking phases are ubiquitous in layered quantum materials, and often compete with other phases such as superconductivity. Preferential suppression of the symmetry broken phases by light has been used to explain non-equilibrium light induced superconductivity, metallicity, and the creation of metastable states. Key to understanding how these phases emerge is understanding how C4 symmetry is restored. A leading approach is based on time-dependent Ginzburg-Landau theory, which explains the coherence response seen in many systems. However, we show that, for the case of the single layered manganite La0.5Sr1.5MnO4, the theory fails. Instead, we find an ultrafast inhomogeneous disordering transition in which the mean-field order parameter no longer reflects the atomic-scale state of the system. Our results suggest that disorder may be common to light-induced phase transitions, and methods beyond the mean-field are necessary for understanding and manipulating photoinduced phases.

Quantum fluctuations in the time-dependent BCS–BEC crossover

2008 ◽  
Vol 366 (1877) ◽  
pp. 2813-2820 ◽  
Author(s):  
B.M Breid ◽  
J.R Anglin
Keyword(s):  
Landau Theory ◽  
Einstein Condensate ◽  
Time Dependent ◽  
Integral Approach ◽  
Saddle Point Approximation ◽  
Ginzburg Landau ◽  
Bose Einstein Condensate ◽  
Fermionic Atoms ◽  
Molecular Fields ◽  
Bose Einstein

We describe the time-dependent formation of a molecular Bose–Einstein condensate from a BCS state of fermionic atoms as a result of slow sweeping through a Feshbach resonance. We apply a path integral approach for the molecules, and use two-body adiabatic approximations to solve the atomic evolution in the presence of the classical molecular fields, obtaining an effective action for the molecules. In the narrow resonance limit, the problem becomes semiclassical, and we discuss the growth of the molecular condensate in the saddle point approximation. Considering this time-dependent process as an analogue of the cosmological Zurek scenario, we compare the way condensate growth is driven in this rigorous theory with its phenomenological description via time-dependent Ginzburg–Landau theory.

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