3,665 research outputs found
Observability of a projected new state of matter: a metallic superfluid
Dissipationless quantum states, such as superconductivity and superfluidity,
have attracted interest for almost a century. A variety of systems exhibit
these macroscopic quantum phenomena, ranging from superconducting electrons in
metals to superfluid liquids, atomic vapours, and even large nuclei. It was
recently suggested that liquid metallic hydrogen could form two new unusual
dissipationless quantum states, namely the metallic superfluid and the
superconducting superfluid. Liquid metallic hydrogen is projected to occur only
at an extremely high pressure of about 400 GPa, while pressures on hydrogen of
320 GPa having already been reported. The issue to be adressed is if this state
could be experimentally observable in principle. We propose four experimental
probes for detecting it.Comment: in print in Phys. Rev. Let
Characteristic length scales and formation of vortices in the Abelian Higgs model in the presence of a uniform background charge
In this brief report we consider a non-local Abelian Higgs model in the
presence of a neutralizing uniform background charge. We show that such a
system possesses vortices which key feature is a strong radial electric field.
We estimate the basic properties of such an object and characteristic length
scales in this model.Comment: Replaced with journal version. Some minor change
Fractional-flux vortices and spin superfluidity in triplet superconductors
We discuss a novel type of fractional flux vortices along with integer flux
vortices in Kosterlitz-Thouless transitions in a triplet superconductor. We
show that under certain conditions a spin-triplet superconductor should exhibit
a novel state of {\it spin superfluidity} without superconductivity.Comment: Physical Review Lettes, in print. v2: references added, v3:
discussion of several points extended according to referee request. Latest
updates and links to related papers are available at my homepage
http://people.ccmr.cornell.edu/~egor
Dual neutral variables and knot solitons in triplet superconductors
In this paper we derive a dual presentation of free energy functional for
spin-triplet superconductors in terms of gauge-invariant variables. The
resulting equivalent model in ferromagnetic phase has a form of a version of
the Faddeev model. This allows one in particular to conclude that spin-triplet
superconductors allow formation of stable finite-length closed vortices (the
knotted solitons).Comment: Replaced with version published in PRL (added a discussion of the
effect of the coupling of the fields {\vec s} and {\vec C} on knot
stability). Latest updates of the paper and miscellaneous links related to
knotted solitons are also available at the homepage of the author
http://www.teorfys.uu.se/PEOPLE/egor/ . Animations of knotted solitons by
Hietarinta and Salo are available at
http://users.utu.fi/h/hietarin/knots/c45_p2.mp
Preemptive vortex-loop proliferation in multicomponent interacting Bose--Einstein condensates
We use analytical arguments and large-scale Monte Carlo calculations to
investigate the nature of the phase transitions between distinct complex
superfluid phases in a two-component Bose--Einstein condensate when a
non-dissipative drag between the two components is being varied. We focus on
understanding the role of topological defects in various phase transitions and
develop vortex-matter arguments allowing an analytical description of the phase
diagram. We find the behavior of fluctuation induced vortex matter to be much
more complex and substantially different from that of single-component
superfluids. We propose and investigate numerically a novel drag-induced
``preemptive vortex loop proliferation'' transition. Such a transition may be a
quite generic feature in many multicomponent systems where symmetry is restored
by a gas of several kinds of competing vortex loops.Comment: 12 pages, 10 figures. Submitted to Physical Review
Baryonic Bound State of Vortices in Multicomponent Superconductors
We construct a bound state of three 1/3-quantized Josephson coupled vortices
in three-component superconductors with intrinsic Josephson couplings, which
may be relevant with regard to iron-based superconductors. We find a Y-shaped
junction of three domain walls connecting the three vortices, resembling the
baryonic bound state of three quarks in QCD. The appearance of the Y-junction
(but not a Delta-junction) implies that in both cases of superconductors and
QCD, the bound state is described by a genuine three-body interaction (but not
by the sum of two-body interactions). We also discuss a
confinement/deconfinement phase transition.Comment: 11 pages, 3 figures, one section on confinement/deconfinement
transition added, published versio
Vortices with fractional flux in two-gap superconductors and in extended Faddeev model
We discuss vortices allowed in two-gap superconductors, bilayer systems and
in equivalent extended Faddeev model. We show that in these systems there exist
vortices which carry an arbitrary fraction of magnetic flux quantum. Besides
that we discuss topological defects which do not carry magnetic flux and
describe features of ordinary one-magnetic-flux-quantum vortices in the two-gap
system. The results should be relevant for the newly discovered two-band
superconductor .Comment: v2 references added, v3 journal version, presentation improved. Links
to related papers are available at the home page of the author
http://www.teorfys.uu.se/PEOPLE/ego
Spin-Charge Separation and the Pauli Electron
The separation between the spin and the charge converts the quantum
mechanical Pauli Hamiltonian into the Hamiltonian of the non-Abelian
Georgi-Glashow model, notorious for its magnetic monopoles and confinement. The
independent spin and charge fluctuations both lead to the Faddeev model,
suggesting the existence of a deep duality structure and indicating that the
fundamental carriers of spin and charge are knotted solitons.Comment: 7 pages; v2: new results added, references update
The phases of deuterium at extreme densities
We consider deuterium compressed to higher than atomic, but lower than
nuclear densities. At such densities deuterium is a superconducting quantum
liquid. Generically, two superconducting phases compete, a "ferromagnetic" and
a "nematic" one. We provide a power counting argument suggesting that the
dominant interactions in the deuteron liquid are perturbative (but screened)
Coulomb interactions. At very high densities the ground state is determined by
very small nuclear interaction effects that probably favor the ferromagnetic
phase. At lower densities the symmetry of the theory is effectively enhanced to
SU(3), and the quantum liquid enters a novel phase, neither ferromagnetic nor
nematic. Our results can serve as a starting point for investigations of the
phase dynamics of deuteron liquids, as well as exploration of the stability and
dynamics of the rich variety of topological objects that may occur in phases of
the deuteron quantum liquid, which range from Alice strings to spin skyrmions
to Z_2 vortices.Comment: 9 pages, 6 figures; v2: fixed typo
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