426 research outputs found
Superfluidity breakdown of periodic matter waves in quasi-one-dimensional annular traps via resonant scattering with moving defects
Get PDFWe investigate, both analytically and numerically, the quasisuperfluidity properties of periodic Bose-Einstein
condensates (BECs) in a quasi-one-dimensional (1D) ring with optical lattices (OL) of different kinds (linear
and nonlinear) and with a moving defect of an infinite mass inside. To study the dynamics of the condensate
we used a mean-field approximation describing the condensate by use of the Gross-Pitaevskii equation for the
order parameter. We show that the resonant scattering of sound Bloch waves with the defect profoundly affect
BEC superfluidity. In particular, a moving defect always leads to the breakdown of superfluidity independently
of the value of its velocity. For weak periodic potentials the superfluidity breakdown may occur on a very long
time scale (quasisuperfluidity) but the breakdown process can be accelerated by increasing the strength of the
OL. Quite remarkably, we find that when the length of the ring is small enough to imply the discreteness of the
reciprocal space, it becomes possible to avoid the resonant scattering and to restore quasi-superfluidity
Superfluidity of Bose-Einstein condensates in toroidal traps with nonlinear lattices
Get PDFSuperfluid properties of Bose-Einstein condensates (BEC) in toroidal quasi-one-dimensional traps are
investigated in the presence of periodic scattering length modulations along the ring. The existence of several types of stable periodic waves, ranging from almost uniform to very fragmented chains of weakly interacting and equally spaced solitons, is demonstrated.We show that these waves may support persistent atomic currents and sound waves with spectra of Bogoliubov type. Fragmented condensates can be viewed as arrays of Josephson junctions and the current as a BEC manifestation of the dc-Josephson effect. The influence of linear defects on BEC superfluidity has been also investigated.We found that for subcritical velocities, linear defects that are static with respect to the lattice (while the condensate moves in respect to both the optical lattice and the defect) preserve the BEC superfluidity.Fundação para a Ciência e a TecnologiaMinistero dell Istruzione, dell’ Universitá e della Ricerca, ItalyMinistery of Education, Youth and Sports of the Czech Republi
Spectral linewidths of Josephson oscillators
Get PDFWe show that the linewidth of a Josephson flux-flow oscillator has the same functional dependence on temperature, static, and dynamic resistances as the ones of Josephson single-fluxon oscillators and small Josephson junctions. This suggests a universal formula for the linewidth of Josephson oscillators
Dissipative periodic waves, solitons, and breathers of the nonlinear Schrodinger equation with complex potentials
No full textExact solutions for the generalized nonlinear Schrodinger equation with inhomogeneous complex linear and nonlinear potentials are found. We have found localized and periodic solutions for a wide class of localized and periodic modulations in the space of complex potentials and nonlinearity coefficients. Examples of stable and unstable solutions are given. We also demonstrated numerically the existence of stable dissipative breathers in the presence of an additional parabolic trap
Snake-to-isola transition and moving solitons via symmetry-breaking in discrete optical cavities
No full textThis paper continues an investigation into a one-dimensional lattice equation that models the light field in a system comprised of a periodic array of pumped optical cavities with saturable nonlinearity. The additional effects of a spatial gradient of the phase of the pump field are studied, which in the presence of loss terms is shown to break the spatial reversibility of the steady problem. Unlike for continuum systems, small symmetry-breaking is argued to not lead directly to moving solitons, but there remains a pinning region in which there are infinitely many distinct stable stationary solitons of arbitrarily large width. These solitons are no-longer arranged in a homoclinic snaking bifurcation diagrams, but instead break up into discrete isolas. For large enough symmetry-breaking, the fold bifurcations of the lowest intensity solitons no longer overlap, which is argued to be the trigger point of moving localised structures. Due to the dissipative nature of the problem, any radiation shed by these structures is damped and so they appear to be true attractors. Careful direct numerical simulations reveal that branches of the moving solitons undergo unsual hysteresis with respect to the pump, for sufficiently large symmetry breaking
Bio-phenol formaldehyde (BPF) resoles prepared using phenolic extracts from the biocrude oils derived from hydrothermal liquefaction of hydrolysis lignin
No full textIn this work, hydrolysis lignin, as a low-value feedstock, was liquefied in ethanol/water co-solvents (50:50, v/v) at 350 °C for 30 min, with or without the use of hematite ore as the catalyst. Following this, the resulting bio-crude oil was applied as the feedstock for the preparation of neat phenol formaldehyde (PF) resole and bio-phenol formaldehyde (BPF) resoles. The net PF resole was prepared by using the whole bio-crude oil, while, the phenolic extracts from the crude oil together with 50% of phenol were employed for the preparation of BPF resoles. The results displayed that although the BPF resole contained a higher free formaldehyde and less thermally stable than neat PF resole, a lower curing temperature was adopted for BPF resole compared to neat PF resole. By analyzing their physical properties, it was observed that the dry bonding strength of BPF resoles was higher than that of neat PF resole. Most importantly, the dry and wet strengths of BPF resole met the requirements for using as an adhesive for plywood bonding. Overall, it can be concluded that the bio-crude oil-derived phenolic extracts from HTL of hydrolysis lignin is a suitable feedstock for producing value-added BPF with potential use as a wood adhesive.Natural Sciences and Engineering Research Council of Canada (NSERC)Natural Scientific Foundation of Chin
Interactive Video Stories from User Generated Content: a School Concert Use Case
No full textFrantzis, M., Zsombori, V., Ursu, M.F., Laiola-Guimares, R., Kegel, I., Craigie, R., 2012. “Interactive Video Stories from User Generated Content: a School Concert Use Case”. In Proceedings of the Fifth International Conference on Digital Storytelling, in association with AAAI, Nov 2012, San Sebastian, Spain, LNCS vol. 7648, pp. 183-195
Low Temperature Physics V. 25, I. 08
No full textdc.description[en_US]Low Temperature Physics -- August 1999
Volume 25, Issue 8, pp. 571-746
80th Birth Anniversary of Boris Ieremievich Verkin(1919���1990)
Full Text: PDF (81 kB)
De Haas���van Alphen oscillation in both the normal and superconducting mixed states of NbSe2, CeRu2, URu2Si2, and UPd2Al3 (Review Article)
Y. Inada and Y. Onuki
Full Text: PDF (1077 kB)
QUANTUM LIQUIDS AND QUANTUM CRYSTALS
Growth and dissolution kinetics of 3He inclusions in phase-separated 3He���4He solid mixtures
A. N. Gan'shin, V. N. Grigor'ev, V. A. Maidanov, N. F. Omelaenko, A. A. Penzev, E. Ya. Rudavskii, A. S. Rybalko, and Yu. A. Tokar
Full Text: PDF (252 kB)
Spin dynamics of 3He-B with dissipation for the general spin-orbital configurations
G. Kharadze and N. Suramlishvili
Full Text: PDF (61 kB)
SUPERCONDUCTIVITY,HIGH-TEMPERATURE SUPERCONDUCTIVITY
De Haas���van Alphen effect and superconductivity
L. P. Gor'kov
Full Text: PDF (40 kB)
Magnetic properties of conventional superconductors with columnar defects
Gregory M. Braverman, Sergey A. Gredeskul, and Yshai Avishai
Full Text: PDF (271 kB)
Cooper instability in the occupation dependent hopping Hamiltonians
H. Boyaci and I. O. Kulik
Full Text: PDF (162 kB)
Superconducting and normal properties of the set of Mo/Si superlattices with variable Si layer thickness
M. Yu. Mikhailov, O. I. Yuzephovich, A. S. Pokhila, Yu. V. Bomze, N. Ya. Fogel, I. M. Dmitrenko, S. A. Yulin, A. S. Sidorenko, O. B. Moldovan, and E. I. Buchstab
Full Text: PDF (75 kB)
LOW-TEMPERATURE MAGNETISM
Low-temperature magnetic properties and stress effects in glassy Fe-B alloys: the eutectic region
A. B. Beznosov, E. L. Fertman, V. V. Eremenko, V. A. Desnenko, and V. Z. Bengus
Full Text: PDF (56 kB)
Raman scattering and phase transitions in mixed crystals K1���x(NH4)xH2PO4
Yu. A. Popkov, A. V. Van'kevich, I. A. Taranova, E. M. Savchenko, and L. A. Shuvalov
Full Text: PDF (77 kB)
ELECTRONIC PROPERTIES OF METALS AND ALLOYS
Nonquantum oscillations associated with the dynamics of an electron in superlattice
A. M. Kosevich and I. D. Wagner
Full Text: PDF (78 kB)
Coupling of electromagnetic and acoustic modes in metals
L. T. Tsymbal, A. N. Cherkasov, and O. F. Panchenko
Full Text: PDF (172 kB)
Electromagnetic waves in organic conductors under strong magnetism of conduction electrons
V. G. Peschansky and D. I. Stepanenko
Full Text: PDF (60 kB)
Effect of pressure on the Fermi surface and electronic structure of ErGa3
V. B. Pluzhnikov, A. Czopnik, O. Eriksson, G. E. Grechnev, and Yu. V. Fomenko
Full Text: PDF (93 kB)
"High-temperature" oscillations of bismuth conductivity in the ultra-quantum limit
Vit. B. Krasovitsky, V. V. Khotkevich, A. G. M. Jansen, and P. Wyder
Full Text: PDF (79 kB)
Effects of alloying and pressure on magnetic properties of itinerant intermetallic compound UFe2
A. S. Panfilov, I. V. Svechkarev, P. Diko, M. Mihalik, and A. Zentko
Full Text: PDF (121 kB)
LOW-DIMENSIONAL AND DISORDERED SYSTEMS
Cooper pairing of two-dimensional electrons in a quantizing magnetic field and the fractional quantum Hall effect
E. A. Pashitskii
Full Text: PDF (190 kB)
The ground state of the "frozen" electron phase in two-dimensional narrow-band conductors with a long-range interelectron repulsion. Stripe formation and effective lowering of dimension
A. A. Slutskin, V. V. Slavin, and H. A. Kovtun
Full Text: PDF (103 kB)
PHYSICAL PROPERTIES OF CRYOCRYSTALS
Influence of an orthodeuterium impurity on the thermal conductivity of solid parahydrogen
O. A. Korolyuk, B. Ya. Gorodilov, A. I. Krivchikov, and V. G. Manzhelii
Full Text: PDF (65 kB)
Formation and trapping of electron excitations in neon cryocrystals
I. Ya. Fugol, A. G. Belov, E. I. Tarasova, and E. M. Yurtaeva
Full Text: PDF (162 kB)
LATTICE DYNAMICS
Analysis of thermodynamic properties of fullerite C60
N. A. Aksenova, A. P. Isakina, A. I. Prokhvatilov, and M. A. Strzhemechny
Full Text: PDF (100 kB)
Localization of vibrations near impurity atoms in semi-infinite and infinite linear chains
M. A. Mamalui, E. S. Syrkin, and S. B. Fedosev
Full Text: PDF (130 kB)
LOW-TEMPERATURE PHYSICS OF PLASTICITY AND STRENGTH
Empirical evaluation of electron and phonon drag coefficients for dislocations in Pb- and Al-based alloys
N. V. Isaev, V. D. Natsik, and V. S. Fomenko
Full Text: PDF (56 kB)
BRIEF COMMUNICATIONS
Visualization of the antiferromagnetic insulator���ferromagnetic metal phase transition in manganite Nd0.5Sr0.5MnO3
S. L. Gnatchenko, A. B. Chizhik, I. O. Shklyarevskii, D. N. Merenkov, V. I. Kamenev, Yu. G. Pashkevich, K. V. Kamenev, G. Balakrishnan, and D. McK. Paul
Full Text: PDF (305 kB)dc.description.contributor[en_US]dc.description.contributor[en_US
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