43,216 research outputs found
High-Tc superconductivity originated from strong spin-charge correlation: indication from linear temperature dependence of resistivity
Both the highest- and the linear temperature dependence of the resistivity in
wide temperature range appear at the optimally doped regions of Cu-based
superconductors1,2,3,4,5, and the highest- of Fe-based superconductors6,7 are
also associated with the linear temperature dependence of the resistivity in
normal states near superconducting states. This means that the high temperature
superconductivity and the linear temperature dependence of the resistivity
should be dominated by the same mechanism. This letter on theoretic calculation
clearly shows that strong spin-charge correlation dominated resistivity behaves
the linear temperature dependence, thus high-temperature superconductivity
should be induced by strong spin-charge correlation.Comment: 4pages,V1 has to be delete
Basic principle of superconductivity
The basic principle of superconductivity is suggested in this paper. There
have been two vital wrong suggestions on the basic principle, one is the
relation between superconductivity and the Bose-Einstein condensation (BEC),
and another is the relation between superconductivity and pseudogap.Comment: 4 gage
Basic physics of solid materials
Since the cuprate materials behave many curious properties, the mechanism
that causes high-temperature superconductivity in copper oxide materials
(cuprates) has been a controversial topic. To explain these curious properties,
we must look out the physics what these materials include. In this letter, it
is presented that there are the basic physics (1)-(9) in solid materials. I
divide all solid materials into four categories, explain some properties of
them qualitatively, and suggest some ways to turn a solid material into a
superconductor. Particularly, this letter discusses the differences between the
p-type high-Tc cuprate superconductors, the n-type superconductor Nd2-xCexCuO4,
the BCS-superconductor similar MgB2, and heavy Fermions superconductors.Comment: 5 pages, 3 figures; a new (recent) pape
Pairing with non-opposite momentum in superconductors
The basic feature of the BCS theory is that pairing occurs between electrons
in states with opposite momentum and opposite spins, e.g., between states (k)
and (-k), in which the symbols of vectors are neglected, and later theories
followed the BCS theory. However, since the center of mass for any pair is not
always static, we must consider the pairing between states (k) and (-k+q). In
this letter, we derive a set of self-consistent equations for the correlation
functions associated with the pairs that have non-opposite momentums, in which
we find some new results. This means that some physics associated with
superconductors should be re-explained in futures.Comment: 2pages, 0figure
Possible temperature control DC switch effect between two superconductors
The lifetime of an electron pair could not be unlimited long, on the basis of
this, we suggest a model. The model means that the movements of charge carriers
in a superconductor should have three forms: the single-electron movement, the
single-pair movement, and the revolving around the mass center of two electrons
in a pair. Thus the current in a superconductor has three possible parts.
Similarly, there should be three possible effects in a SIS junction: the
tunneling of single electron, the tunneling of single pair, and the
pair-forming following the pair-breaking. This paper will discuss these
problems and present a possible temperature control DC switch effect between
two superconductors.Comment: superconductivity, 9page
Reverse circling supercurrents along a superconducting ring
The reason why high temperature superconductivity has been being debated is
that many basic ideas in literatures are wrong. This work shows that the
magnetic flux quantum in a superconducting ring have been inaccurately
explained in fact, thus we suggest a reinterpretation of the magnetic flux
quantum in a superconducting ring on the basis of the translations of pairs. We
also predict that the internal and external surface of a superconducting tube
have the reverse circling supercurrents. This means that a more thick tube
could trap a larger amount of flux. Both the magnetic flux quantum and the
reverse circling supercurrents could not be found with the London equation.Comment: superconductivity;6page
Superconductors described with CSM.(a new paper, 2008-10-16)
The properties of the known superconductors can be explained with the
correlations dominated superconducting mechanism (CSM). The correlations have
the spin correlation, the charge correlation and the spin-charge correlation,
and their strengths can be described by the related correlation lengths in
their correlation functions. Our evaluation from many superconductors is that
superconductivities occur if both the spin correlation and the charge
correlation are stronger, and the calculation of a Hubbard model showed that
the spin-charge correlation may govern superconductivities1. Afterwards, this
mechanism has led a model which includes various superconductivities and
magnetisms, and the relation between superconductivities and magnetisms can be
understood on this model2 (these results have been shown by calculations). This
mechanism is very practical, for example, to turn a material into a
superconductor or increase the Tc of a superconductor, what we will do is to
increase the spin-charge correlation. In this letter, we first describe the
relations between the spin-charge correlation, the spin correlation and the
charge correlation, take these relations as the basis of constructing a new
phase diagram, and then classify the known superconductors into various
sections in this phase diagram. This letter also gives a new explanation about
the pressure effect on Tc, the isotope effect on Tc and the pairing symmetry
with the CSM.Comment: 4 pages,2 tables, 1 figur
Coincidence Subwavelength Interference by a Classical Thermal Light
We show that a thermal light random in transverse direction can perform
subwavelength double slit interference in a joint-intensity measurement. This
is the classical version of quantum lithography, and it can be explained with
the correlation of rays instead of the entanglement of photons.Comment: 4 pages, 2 figure
Quantum Lithography in Macroscopic Observations
We study the generalized Young's double-slit interference for the beam
produced in the spontaneously parametric down-conversion (SPDC). We find that
the sub-wavelength lithography can occur macroscopically in both the two-photon
intensity measurement and the single-photon spatial intensity correlation
measurement. We show the visibility and the strength of the interference fringe
related to the SPDC interaction. It may provide a strong quantum lithography
with a moderate visibility in practical application.Comment: 6 pages, 5 Postscript figures, uses revte
N-photon Correlation Functions in N-slit Diffraction Experiments with Thermal Light
We discuss the analytic presentations of the high-order correlation functions
in the N-slit diffraction with thermal light in a recent paper [Phys. Rev.
Lett. 109, 233603 (2012)]. Our analysis shows that the superresolving fringes
in the high-order correlation measurement have two classical counterparts.Comment: 4 pages, 1 figur
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