全文获取类型
收费全文 | 51篇 |
免费 | 0篇 |
专业分类
化学 | 8篇 |
物理学 | 43篇 |
出版年
2022年 | 1篇 |
2016年 | 1篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2009年 | 1篇 |
2007年 | 2篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1905年 | 1篇 |
1904年 | 1篇 |
1903年 | 2篇 |
1902年 | 1篇 |
1901年 | 1篇 |
1900年 | 1篇 |
排序方式: 共有51条查询结果,搜索用时 23 毫秒
1.
It is shown that the dephasing which suppresses the weak localization correction to the conductivity has the same physical origin than pair-breaking in superconductors and thus-following de Gennes-may be expressed in terms of the correlation function of the operator for time reversal. 相似文献
2.
Starting from a model of free Fermions in two dimensions with an arbitrary strong effective interaction, we derive a Ginzburg-Landau theory describing the crossover from BCS-superconductivity to Bose-condensation. We find a smooth crossover from the standard BCS-limit to a Gross-Pitaevski type equation for the order parameter in a Bose superfluid. The mean field transition temperature exhibits a maximum at a coupling strength, where the behaviour crosses over from BCS to Bose like with corresponding values of 2 Δ0/Tc ≈ 5 which are characteristic for high Tc superconductors. 相似文献
3.
4.
W. Zwerger 《Zeitschrift für Physik B Condensed Matter》1994,93(3):333-341
Recent experiments have demonstrated that the numbern of additional electrons on a small metallic island is a staircase function of a continuous external chargen
x
for temperaturesT small compared to the single electron charging energyU. We show that the finite conductanceg of the tunnel barrier connecting the island to the external gate gives rise to quantum fluctuations inn which lead to a smearing of the staircase even at zero temperature. In the experimentally relevant case of wide junctions and in the limit of small conductanceg1 the slope <n>/n
x
at the turning point between two plateaus saturates at a finite value of order 1/g asT0 instead of diverging likeU/T as predicted with thermal fluctuations only. The experimentally observed broadening however is still much larger which is probably due to extrinsic effects. 相似文献
5.
W. Zwerger 《Zeitschrift für Physik B Condensed Matter》1983,54(1):87-91
The problem of quantum coherence in a symmetric double well potential with a dimensionless damping coefficient α for classical motion is studied within a spin 1/2-boson model. The experimentally measured probabilityp(t) of refinding a definite initial state after timet is approximately expressed by the transverse spin relaxation function ?(t), which is determined from a three-pole approximation, that incorporates both the correct long and short time behaviour. For a bare tunnelsplitting δ small compared to the heat bath cutoffω c we find, that the oscillating component of ?(t) is negligible compared to the relaxational one unless α is of orderΔ/ω c . Thusp(t)?(1+exp(?νt))/2 with a mean tunneling rateν proportional to \(\tilde \Delta = \Delta (\Delta /\omega _c )^{\frac{\alpha }{{2 - \alpha }}} \) for α < 2 andT ? \(\tilde \Delta \) and proportional toΔ 2/ω c ·(T/ω c ) α?1 otherwise. The results apply directly to recent measurements of the dynamics of flux states in a SQUID. 相似文献
6.
W. Zwerger 《Zeitschrift für Physik B Condensed Matter》1982,47(2):129-135
The coupling between the phase and the electromagnetic field in the case of a tunnel junction is treated by Feynmans path integral method. It is shown that the elimination of the field leads to a frequency dependent mass for the motion of the phase , which is simply related to the effective dielectric constant of the junction. Considering tunneling as a motion in imaginary time one obtains a polaron like mass enhancement connected to the dielectric function at positive imaginary frequencies, which essentially leads to the Caldeira-Leggett reduction of the elastic tunneling probability. In the weak damping limit it is shown that the emission of real excitations during tunneling is a higher order effect. At low temperatures the damping finally is determined by the linewidth of electromagnetic radiation at the Josephson plasma frequency. 相似文献
7.
We show that strong pairing correlations in Fermi gases lead to the appearance of a gaplike structure in the rf spectrum, both in the balanced superfluid and in the normal phase above the Clogston-Chandrasekhar limit. The average rf shift of a unitary gas is proportional to the ratio of the Fermi velocity and the scattering length with the final state. In the strongly imbalanced case, the rf spectrum measures the binding energy of a minority atom to the Fermi sea of majority atoms. Our results provide a qualitative understanding of recent experiments by Schunck et al. 相似文献
8.
Using the adaptive time-dependent density-matrix renormalization group method for the 1D Hubbard model, the splitting of local perturbations into separate wave packets carrying charge and spin is observed in real time. We show the robustness of this separation beyond the low-energy Luttinger liquid theory by studying the time evolution of single particle excitations and density wave packets. A striking signature of spin-charge separation is found in 1D cold Fermi gases in a harmonic trap at the boundary between liquid and Mott-insulating phases. We give quantitative estimates for an experimental observation of spin-charge separation in an array of atomic wires. 相似文献
9.
We study the dynamic structure factor for density and spin within the crossover from BCS superfluidity of atomic fermions to the Bose-Einstein condensation of molecules. Both structure factors are experimentally accessible via Bragg spectroscopy and allow for the identification of the pairing mechanism: the spin structure factor allows for the determination of the two particle gap, while the collective sound mode in the density structure reveals the superfluid state. 相似文献
10.
We investigate the physical properties of quasi-1D quantum gases of fermionic atoms confined in harmonic traps. Using the fact that for a homogeneous gas the low-energy properties are exactly described by a Luttinger model, we analyze the nature and manifestations of spin-charge separation, where in the case of atoms "spin" and "charge" refer to two internal atomic states and the atomic mass density, respectively. We discuss the necessary physical conditions and experimental limitations confronting possible experimental implementations. 相似文献