scholarly journals MEMBRANE VACUUM AS A TYPE II SUPERCONDUCTOR

1996 ◽  
Vol 10 (13n14) ◽  
pp. 1695-1705 ◽  
Author(s):  
S. Ansoldi ◽  
A. Aurilia ◽  
E. Spallucci
Keyword(s):  
Field Theory ◽  
Gauge Field ◽  
Ground State ◽  
Gauge Potential ◽  
Type Ii ◽  
Two Phase ◽  
Type Ii Superconductor ◽  
Massive Spin ◽  
Phase Medium ◽  
Physical Thickness

We study a functional field theory of membranes coupled to a rank-three tensor gauge potential. We show that gauge field radiative corrections lead to membrane condensation which turns the gauge field into a massive spin-0 field. This is the Coleman-Weinberg mechanism for membranes. An analogy is also drawn with a type-II superconductor. The ground state of the system consists of a two-phase medium in which the superconducting background condensate is “pierced” by four-dimensional domains, or “bags”, of non-superconducting vacuum. Bags are bounded by membranes whose physical thickness is of the order of the inverse mass acquired by the gauge field.

scholarly journals Spin(p + 1, p + 1) COVARIANT Dp-BRANE BOUND STATES

2001 ◽  
Vol 16 (17) ◽  
pp. 3025-3040 ◽  
Author(s):  
P. SUNDELL
Keyword(s):  
Field Theory ◽  
Ground State ◽  
Bound States ◽  
Type Ii ◽  
Duality Group ◽  
Zero Force ◽  
Force Condition ◽  
The Stability

We construct Spin (p + 1, p + 1) covariant D p-brane bound states by using the fact that the potentials in the RR sector of toroidically compactified type II supergravity transform as a chiral spinor of the T duality group. As an application, we show the invariance of the zero-force condition for a probe D-brane under noncommutative deformations of the background, which gives a holographic proof of the stability of the corresponding field theory ground state under noncommutative deformations. We also identify the Spin (p + 1, p + 1) transformation laws by examining the covariance of the D-brane Lagrangians.

scholarly journals NONPERTURBATIVE APPROACH TO YANG–MILLS THERMODYNAMICS

2005 ◽  
Vol 20 (18) ◽  
pp. 4123-4216 ◽  
Author(s):  
RALF HOFMANN
Keyword(s):  
State Physics ◽  
Phase Transitions ◽  
Density Of States ◽  
Ground State ◽  
Particle Physics ◽  
Scalar Fields ◽  
Temperature Evolution ◽  
Two Phase ◽  
Yang Mills ◽  
Massive Spin

An analytical and nonperturbative approach to SU(2) and SU(3) Yang–Mills thermodynamics is developed and applied. Each theory comes in three phases: A deconfining, a preconfining, and a confining one. We show how macroscopic and inert scalar fields emerge in each phase and how they determine the ground-state physics and the properties of the excitations. While the excitations in the deconfining and preconfining phases are massless or massive gauge modes the excitations in the confining phase are massless or massive spin-1/2 fermions. The nature of the two phase transitions is investigated for each theory. We compute the temperature evolution of thermodynamical quantities in the deconfining and preconfining phase and estimate the density of states in the confining phase. Some implications for particle physics and cosmology are discussed.

HVSR analysis of a layered saturated half-space using diffuse-field theory

2021 ◽  
Vol 226 (1) ◽  
pp. 270-286
Author(s):  
Zhenning Ba ◽  
Qiaozhi Sang ◽  
Jianwen Liang ◽  
Mengtao Wu
Keyword(s):  
Field Theory ◽  
Green’S Function ◽  
Green's Function ◽  
Hankel Transform ◽  
Low Velocity ◽  
Two Phase ◽  
Isotropic Energy ◽  
Layer Sequence ◽  
Impedance Ratio ◽  
Phase Medium

SUMMARY The recently constructed diffuse field theory from isotropic energy equipartition has been well developed in elasticity for full-wave interpretation of horizontal-to-vertical ratio (HVSR), which links the signal autocorrelation with the imaginary part of Green's function. Here, the theory is extended to the saturated layered medium within the framework of Biot's theory to account for the offshore environment. The imaginary parts of Green's functions are obtained using direct stiffness method accompanied with Fourier–Hankel transform. In particular, the upgoing wave amplitudes are modified to tackle the overflow during wavenumber integral and allow for fast calculations. After validating the method from the perspectives of Green's function calculation, emphasis is laid on evaluating the inaccuracies of HVSR calculation induced by model misuses in the lack of prior geological and geotechnical information. The numerical results considering the effects of layer sequence, impedance ratio, porosity and drainage condition show that the predominant frequency of the one-phase medium is slightly less than the two-phase medium with the maximum shift no more than 0.1 Hz, while their amplitude differences can be prominent as impedance ratio and porosity increase, with the maximum difference up to 29 per cent. The shallowest soft layer has the dominant effects on HVSR amplitudes, whereas the buried low-velocity layer at depth over one-wavelength contributes little to the peak amplitude. Finally, the method is applied to a realistic case at Mirandola, Northorn Italy, which suffered extensive liquefaction-induced damages in 2012 Emilia earthquake. The well identified pattern of the experimental HVSR using the two-phase medium model illustrates the application potential of our method to further assist the subsurface geology retrieval.

scholarly journals NOVEL TOPOLOGICAL INVARIANT IN THE U(1) GAUGE FIELD THEORY

2007 ◽  
Vol 22 (29) ◽  
pp. 2201-2208 ◽  
Author(s):  
YISHI DUAN ◽  
XINHUI ZHANG ◽  
LI ZHAO
Keyword(s):  
Field Theory ◽  
Gauge Field ◽  
Potential Theory ◽  
Three Dimensional ◽  
Current Theory ◽  
Topological Invariant ◽  
Gauge Potential ◽  
Gauge Field Theory ◽  
Knot Invariant ◽  
Topological Current

Based on the decomposition of U(1) gauge potential theory and the ϕ-mapping topological current theory, the three-dimensional knot invariant and a four-dimensional new topological invariant are discussed in the U(1) gauge field.

Interfacial studies in Nb3Sn superconductors

1991 ◽  
Vol 49 ◽  
pp. 590-591
Author(s):  
Ernest L. Hall ◽  
Lee E. Rumaner ◽  
Mark G. Benz
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Flux Pinning ◽  
Size Control ◽  
High Magnetic Fields ◽  
Type Ii ◽  
Reaction Interface ◽  
Liquid Diffusion ◽  
Type Ii Superconductor ◽  
Grain Size Control

The intermetallic compound Nb3Sn is a type-II superconductor of interest because it has high values of critical current density Jc in high magnetic fields. One method of forming this compound involves diffusion of Sn into Nb foil containing small amounts of Zr and O. In order to maintain high values of Jc, it is important to keep the grain size in the Nb3Sn as small as possible, since the grain boundaries act as flux-pinning sites. It has been known for many years that Zr and O were essential to grain size control in this process. In previous work, we have shown that (a) the Sn is transported to the Nb3Sn/Nb interface by liquid diffusion along grain boundaries; (b) the Zr and O form small ZrO2 particles in the Nb3Sn grains; and (c) many very small Nb3Sn grains nucleate from a single Nb grain at the reaction interface. In this paper we report the results of detailed studies of the Nb3Sn/Nb3Sn, Nb3Sn/Nb, and Nb3Sn/ZrO2 interfaces.

Spin-echo observation of radio frequency induced flux lattice annealing (RIFLA) in a type-II superconductor

1999 ◽  
Vol 09 (PR10) ◽  
pp. Pr10-49-Pr10-51
Author(s):  
W. G. Clark ◽  
F. Lefloch ◽  
M. E. Hanson ◽  
W. H. Wong
Keyword(s):  
Radio Frequency ◽  
Spin Echo ◽  
Type Ii ◽  
Type Ii Superconductor ◽  
Flux Lattice

ROTATIONAL MAGNETIC PROCESSES IN A TYPE-II SUPERCONDUCTOR

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-2189-C8-2190
Author(s):  
Liwen Liu ◽  
J. S. Kouvel ◽  
T. O. Brun
Keyword(s):  
Type Ii ◽  
Type Ii Superconductor

Riemann–Weyl in Deleuze's Bergsonism and the Constitution of the Contemporary Physico-Mathematical Space

2015 ◽  
Vol 9 (1) ◽  
pp. 59-87 ◽  
Author(s):  
Martin Calamari
Keyword(s):  
Field Theory ◽  
Gauge Field ◽  
Fibre Bundle ◽  
History Of Mathematics ◽  
Gauge Field Theory ◽  
Contemporary Science ◽  
Explicit Mention ◽  
History Of ◽  
Key Features ◽  
Bernhard Riemann

In recent years, the ideas of the mathematician Bernhard Riemann (1826–66) have come to the fore as one of Deleuze's principal sources of inspiration in regard to his engagements with mathematics, and the history of mathematics. Nevertheless, some relevant aspects and implications of Deleuze's philosophical reception and appropriation of Riemann's thought remain unexplored. In the first part of the paper I will begin by reconsidering the first explicit mention of Riemann in Deleuze's work, namely, in the second chapter of Bergsonism (1966). In this context, as I intend to show first, Deleuze's synthesis of some key features of the Riemannian theory of multiplicities (manifolds) is entirely dependent, both textually and conceptually, on his reading of another prominent figure in the history of mathematics: Hermann Weyl (1885–1955). This aspect has been largely underestimated, if not entirely neglected. However, as I attempt to bring out in the second part of the paper, reframing the understanding of Deleuze's philosophical engagement with Riemann's mathematics through the Riemann–Weyl conjunction can allow us to disclose some unexplored aspects of Deleuze's further elaboration of his theory of multiplicities (rhizomatic multiplicities, smooth spaces) and profound confrontation with contemporary science (fibre bundle topology and gauge field theory). This finally permits delineation of a correlation between Deleuze's plane of immanence and the contemporary physico-mathematical space of fundamental interactions.

SYNTHESIS OF HYDROGEN IN ACOUSTOPLASMA DISCHARGE IN A LIQUID-PHASE STREAM

2019 ◽  
pp. 42-48 ◽  
Author(s):  
N. A. Bulychev
Keyword(s):  
Liquid Phase ◽  
Organic Compounds ◽  
Electrode Materials ◽  
Solid Phase ◽  
Plasma Discharge ◽  
Raw Material ◽  
Two Phase ◽  
Reduced Pressure ◽  
External Power Source ◽  
Phase Medium

In this paper, the plasma discharge in a high-pressure fluid stream in order to produce gaseous hydrogen was studied. Methods and equipment have been developed for the excitation of a plasma discharge in a stream of liquid medium. The fluid flow under excessive pressure is directed to a hydrodynamic emitter located at the reactor inlet where a supersonic two-phase vapor-liquid flow under reduced pressure is formed in the liquid due to the pressure drop and decrease in the flow enthalpy. Electrodes are located in the reactor where an electric field is created using an external power source (the strength of the field exceeds the breakdown threshold of this two-phase medium) leading to theinitiation of a low-temperature glow quasi-stationary plasma discharge.A theoretical estimation of the parameters of this type of discharge has been carried out. It is shown that the lowtemperature plasma initiated under the flow conditions of a liquid-phase medium in the discharge gap between the electrodes can effectively decompose the hydrogen-containing molecules of organic compounds in a liquid with the formation of gaseous products where the content of hydrogen is more than 90%. In the process simulation, theoretical calculations of the voltage and discharge current were also made which are in good agreement with the experimental data. The reaction unit used in the experiments was of a volume of 50 ml and reaction capacity appeared to be about 1.5 liters of hydrogen per minute when using a mixture of oxygen-containing organic compounds as a raw material. During their decomposition in plasma, solid-phase products are also formed in insignificant amounts: carbon nanoparticles and oxide nanoparticles of discharge electrode materials.

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