共查询到20条相似文献,搜索用时 31 毫秒
1.
M. Takigawa M. Ichioka K. Machida 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(3):303-311
Thermal conductivity κ
xx(T) under a field is investigated in d
x2 - y2-wave superconductors and isotropic s-wave superconductors by the linear response theory, using a microscopic wave function of the vortex lattice states. To study
the origin of the different field dependence of κxx(T) between higher and lower temperature regions, we analyze the spatially-resolved thermal conductivity around a vortex at
each temperature, which is related to the spectrum of the local density of states. We also discuss the electric conductivity
in the same formulation for a comparison.
Received 8 December 2001 and Received in final form 20 March 2002 Published online 6 June 2002 相似文献
2.
G. Benenti G. Casati D.L. Shepelyansky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(2):265-272
We model an isolated quantum computer as a two-dimensional lattice of qubits (spin halves) with fluctuations in individual
qubit energies and residual short-range inter-qubit couplings. In the limit when fluctuations and couplings are small compared
to the one-qubit energy spacing, the spectrum has a band structure and we study the quantum computer core (central band) with
the highest density of states. Above a critical inter-qubit coupling strength, quantum chaos sets in, leading to quantum ergodicity
of eigenstates in an isolated quantum computer. The onset of chaos results in the interaction induced dynamical thermalization
and the occupation numbers well described by the Fermi-Dirac distribution. This thermalization destroys the noninteracting
qubit structure and sets serious requirements for the quantum computer operability.
Received 3 July 2001 and Received in final form 9 September 2001 相似文献
3.
N. Bouarissa 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,26(2):153-158
Dependencies of electronic structure and lattice properties of InN with zinc-blende structure on hydrostatic pressure are
presented based on band structures computed using the empirical pseudopotential method. The pressure behavior of the pseudopotential
form factors have been analyzed. The effect of pressure on the density of states has been examined. Trends in bonding and
ionicity under pressure are also discussed. Our results show as well that the absolute value of the Fourier transform of the
valence charge density might be useful in the prediction of the phase transition in zinc-blende materials.
Received 25 May 2001 and Received in final form 16 January 2002 相似文献
4.
K. Parlinski 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(3):283-285
Using the density functional theory the structural and magnetic properties of iron borate under high pressure have been studied.
At about P
= 22.7 GPa a first order phase transition to the phase described by the same space group Rc has been found. The phase transition is accompanied by a 9% volume change of the unit cell, a four times decrease of the
magnetic moment on Fe, an increase of the charge density at Fe, and a disappearance of the energy gap in the electronic density
of states.
Received 21 September 2001 and Received in final form 6 January 2002 Published online 6 June 2002 相似文献
5.
J.M. Cerveró A. Rodrıguez 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,30(2):239-251
We present the exact diagonalization of the Schr?dinger operator corresponding to a periodic potential with N deltas of different couplings, for arbitrary N. This basic structure can repeat itself an infinite number of times. Calculations of band structure can be performed with
a high degree of accuracy for an infinite chain and of the correspondent eigenlevels in the case of a random chain. The main
physical motivation is to modelate quantum wire band structure and the calculation of the associated density of states. These
quantities show the fundamental properties we expect for periodic structures although for low energy the band gaps follow
unpredictable patterns. In the case of random chains we find Anderson localization; we analize also the role of the eigenstates
in the localization patterns and find clear signals of fractality in the conductance. In spite of the simplicity of the model
many of the salient features expected in a quantum wire are well reproduced.
Received 24 June 2002 Published online 29 November 2002 相似文献
6.
B. Dóra A. Virosztek 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,22(2):167-178
We consider the possibility of formation of an unconventional spin density wave (USDW) in quasi-one-dimensional electronic
systems. In analogy with unconventional superconductivity, we develop a mean field theory of SDW allowing for the momentum
dependent gap Δ() on the Fermi surface. Conditions for the appearance of such a low temperature phase are investigated. The excitation spectrum
and basic thermodynamic properties of the model are found to be very similar to those of d-wave superconductors in spite of the different topology of their Fermi surfaces. Several correlation functions are calculated,
and the frequency dependent conductivity is evaluated for various gap functions. The latter is found to reflect the maximum
gap value, however with no sharp onset for absorbtion.
Received 19 February 2001 相似文献
7.
M. Krawiec B.L. Györffy J.F. Annett 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(2):163-176
We study the ground state properties of a superconductor-ferromagnet-insulator trilayer on the basis of a Hubbard Model featuring
exchange splitting in the ferromagnet and electron-electron attraction in the superconductor. We solve the spin-polarized
Hartree-Fock-Gorkov equations together with the Maxwell's equation (Ampere's law) fully self-consistently with respect to
the order parameter and the current. For certain values of the exchange splitting we find that a spontaneous spin polarized
current is generated in the ground state and is intimately related to Andreev bound states at the Fermi level. Moreover, the
polarization of the current strongly depends on the band filling.
Received 23 September 2002 / Received in final form 13 December 2002 Published online 1st April 2003
RID="a"
ID="a"e-mail: m.a.krawiec@bristol.ac.uk 相似文献
8.
U. Yurtsever D. Strekalov J.P. Dowling 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):365-371
A quantum gravity-gradiometer consists of two spatially separated ensembles of atoms interrogated by pulses of a common laser
beam. The laser pulses cause the probability amplitudes of atomic ground-state hyperfine levels to interfere, producing two,
motion-sensitive, phase shifts, which allow the measurement of the average acceleration of each ensemble, and, via simple
differencing, of the acceleration gradient. Here we propose entangling the quantum states of atoms from the two ensembles
prior to the pulse sequence, and show that entanglement encodes their relative acceleration in a single interference phase
which can be measured directly, with no need for differencing.
Received 6 June 2002 / Received in final form 25 October 2002 Published online 28 January 2003 相似文献
9.
J. Lages D.L. Shepelyansky 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(1):129-133
We study analytically and numerically the problem of two particles with a long range attractive interaction on a two-dimensional
(2d) lattice with disorder. It is shown that below some critical disorder the interaction creates delocalized coupled states
near the Fermi level. These states appear inside well localized noninteracting phase and have a form of two-particle ring
which diffusively propagates over the lattice.
Received 29 September 2000 and Received in final form 15 January 2001 相似文献
10.
The configuration-dependent cranked Nilsson-Strutinsky approach has been employed to study the properties and band structures
at high spin in the Z = N odd-odd nuclei 46V and 50Mn. The observed bands are explained and terminating states are confirmed by the calculations. The calculated and observed
bands are in good agreement without normalization, especially for terminating states. Possible bands with rotation around
the intermediate axis and the effect of γ-deformation on the total energy of several interesting configurations are discussed.
Received: 2 April 2002 / Accepted: 27 January 2003 / Published online: 15 April 2003 相似文献
11.
G. Yang K. Maki 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(1):61-65
We study theoretically the effect of impurity scattering in f-wave (or E2u) superconductors. The quasi-particle density of states of f-wave superconductor is very similar to the one for d-wave superconductor as in hole-doped high T
c
cuprates. Also in spite of anisotropy in Δ(
), both the reduced superfluid density and the reduced electronic thermal conductivity is completely isotropic.
Received 11 October 2000 相似文献
12.
Vinod Kumar Pragya Das R.P. Singh S. Muralithar R.K. Bhowmik 《The European Physical Journal A - Hadrons and Nuclei》2003,17(2):153-157
The fusion evaporation reaction 122Sn(14N, 4n)132La was used to populate the high-spin states of 132La at the beam energy of 60 MeV. A new band consisting of mostly E2 transitions has been discovered. This band has the interesting links to the ground state 2- and the isomeric state 6-. A new transition of energy 351 keV connecting the low-spin states of the positive-parity band based on the πh
11/2 ⊗ νh
11/2 particle configuration, has been found. This has played a very important role in resolving the existing ambiguities and inconsistencies
in the spin assignment of the band head.
Received: 12 August 2002 / Accepted: 18 March 2003 / Published online: 7 May 2003 相似文献
13.
We study the nature of one-electron eigen-states in a one-dimensional diluted Anderson model where every Anderson impurity is diluted by a periodic function f(l). Using renormalization group and transfer matrix techniques, we provide accurate estimates of the extended states which appear in this model, whose number depends on the symmetry of the diluting function f(l). The density of states (DOS) for this model is also numerically obtained and its main features are related to the symmetries of the diluting function f(l). Further, we show that the emergence of extended states promotes a sub-diffusive spread of an initially localized wave-packet.Received: 7 July 2003, Published online: 19 November 2003PACS:
63.50. + x Vibrational states in disordered systems - 63.22. + m Phonons or vibrational states in low-dimensional structures and nanoscale materials - 62.30. + d Mechanical and elastic waves; vibrations 相似文献
14.
R. Julin P.T. Greenlees K. Helariutta P. Jones S. Juutinen A.-P. Leppänen H. Kankaanpää A. Keenan H. Kettunen P. Kuusiniemi M. Leino M. Muikku P. Nieminen J. Pakarinen P. Rahkila J. Uusitalo D.T. Joss S.J. Williams D.G. Jenkins N.-S. Kelsall R. Wadsworth K. Hauschild A. Hürstel W. Korten Y. Le Coz A.N. Andreyev P. Van Duppen M. Huyse K. Van de Vel C.J. Moore C.D. O'Leary R.D. Page M.J. Taylor W. Reviol M.B. Smith 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):189-193
The JYFL gas-filled recoil separator RITU, combined with Ge detector arrays and a SACRED magnetic solenoid spectrometer, has
been successfully employed in recoil-decay-tagging (RDT) experiments in order to probe structures of very neutron-deficient
heavy nuclei. The present contribution focuses on the light Pb region where the new data extend the systematics of shape-coexisting
yrast states towards the proton dripline. Similarities between band structures and their relation to possible multi-particle
multi-hole intruder excitations will be discussed.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: rauno.julin@phys.jyu.fi 相似文献
15.
T. Bäck B. Cederwall R. Wyss A. Johnson J. Cederkäll M. Devlin J. Elson D.R. LaFosse F. Lerma D.G. Sarantites R.M. Clark P. Fallon I.Y. Lee A.O. Macchiavelli R.W. Macleod 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):391-397
High-spin states in 88Mo were studied using the Gammasphere germanium detector array in conjunction with the Microball CsI(Tl) charged-particle
detector system. Three γ-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational
bands observed in the neighbouring A= 80 region have been identified and assigned to the nucleus 88Mo. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole
deformation of β2≈ 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total
routhian surface calculations. All three bands are assigned to two-quasi-particle proton configurations at superdeformed shape.
Received: 20 May 1999 / Revised version: 25 August 1999 相似文献
16.
D.F. Underwood T. Kippeny S.J. Rosenthal 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):241-244
The dynamics of photo-generated electrons and holes in CdSe quantum dots have been studied using the femtosecond fluorescence
upconversion technique, permitting an unambiguous examination of the excited state. The band edge emission shows an expected
size dependence on the decay rate. We find that the deep trap emission is coupled to the band edge fluorescence, implicating
surface states as important factors in the excited state lifetime of the hole. As a factor of the overall efficiency of solar
cells, the rate of charge separation and the fate of the exciton are important considerations in the design of nanocrystal-based
photovoltaic devices.
Received 30 November 2000 相似文献
17.
18.
A. Bauchet I. Deloncle M.-G. Porquet A. Astier N. Buforn M. Meyer S. Perriès N. Redon B.J.P. Gall F. Hoellinger N. Schulz G. Duchêne S. Courtin Ts. Venkova P.A. Butler N. Amzal R.D. Herzberg A. Chewter R. Cunningham M. Houry R. Lucas W. Urban A. Nowak E. Piasecki J. Duprat C. Petrache T. Kröll 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):145-150
High-spin states of 103
43Tc have been identified for the first time, this nucleus being produced as fission fragment following the fusion reaction
37Cl + 176Yb at 170 MeV bombarding energy. The high-spin level scheme has been built from the prompt gamma rays detected using the Euroball
III array. It exhibits similarities with those of the neighbouring isotopes and isotones. All the band head configurations
observed in the 97-105Tc isotopes are identified from the behaviour of the rotational bands built on them. The single-proton states located around
the Fermi level are discussed as a function of deformation of these nuclei.
Received: 19 January 2001 / Accepted: 23 February 2001 相似文献
19.
H. Ikezoe T. Ikuta S. Mitsuoka Y. Nagame I. Nishinaka K. Tsukada T. Ohtsuki T. Kuzumaki J. Lu 《The European Physical Journal A - Hadrons and Nuclei》1998,2(4):379-382
Mean lifetimes of the high spin states in the yrast band of 126Ba were measured by using the Doppler shift attenuation method in connection with the reaction 116Sn (16O, 2p4n)126Ba at a beam energy of 73 MeV. The corresponding normalized B(E2) values are obviously reduced in the vicinity of the backbending.
The results are compared with the theoretical predictions based on a realistic nucleon-nucleon interaction.
Received: 9 June 1997 / Revised version: 16 October 1997 相似文献
20.
R. Krücken S.J. Asztalos R.M. Clark M.A. Deleplanque R.M. Diamond P. Fallon I.Y. Lee A.O. Macchiavelli G.J. Schmid F.S. Stephens K. Vetter Jing-Ye Zhang 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):151-155
High-spin states in 112Pd were studied using prompt γ-ray spectroscopy with Gammasphere following heavy-ion-induced fission in the reaction 18O + 208Pb at 91 MeV. A new 8+ level at 2638 keV was discovered with transitions connecting it to the yrast band and the quasi-gamma band. The three, now
established, closely spaced 8+ states indicate a mixing between the ground-state band, s-band, and quasi-gamma band. Several high-spin structures with likely negative parity have been extended to higher spin and
it is proposed that they are based on the νh
11/2(g
7/2
d
5/2) and νh
11/2(s
1/2
d
3/2) configurations.
Received: 28 November 2000 / Accepted: 8 February 2001 相似文献