TY  - JOUR
A1  - Haakh, Harald Richard
A1  - Henkel, Carsten
T1  - Magnetic near fields as a probe of charge transport in spatially dispersive conductors
JF  - The European physical journal : B, Condensed matter and complex systems
N2  - We calculate magnetic field fluctuations above a conductor with a nonlocal response (spatial dispersion) and consider a large range of distances. The cross-over from ballistic to diffusive charge transport leads to a reduced noise spectrum at distances below the electronic mean free path, as compared to a local description. We also find that the mean free path provides a lower limit to the correlation (coherence) length of the near field fluctuations. The short-distance behaviour is common to a wide range of materials, including semiconductors and superconductors. Our discussion is aimed at atom chip experiments where spin-flip transitions give access to material properties with mesoscopic spatial resolution. The results also hint at fundamental limits to the coherent operation of miniaturised atom traps and matter-wave interferometers.
Y1  - 2012
U6  - https://doi.org/10.1140/epjb/e2011-20567-1
SN  - 1434-6028
VL  - 85
IS  - 1
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Bimonte, Giuseppe
A1  - Haakh, Harald Richard
A1  - Henkel, Carsten
A1  - Intravaia, Francesco
T1  - Optical BCS conductivity at imaginary frequencies and dispersion energies of superconductors
N2  - We present an efficient expression for the analytic continuation to arbitrary complex frequencies of the complex optical and ac conductivity of a homogeneous superconductor with an arbitrary mean free path. Knowledge of this quantity is fundamental in the calculation of thermodynamic potentials and dispersion energies involving type-I superconducting bodies. When considered for imaginary frequencies, our formula evaluates faster than previous schemes involving Kramers-Kronig transforms. A number of applications illustrate its efficiency: a simplified low-frequency expansion of the conductivity, the electromagnetic bulk self-energy due to longitudinal plasma oscillations, and the Casimir free energy of a superconducting cavity.
Y1  - 2010
UR  - http://iopscience.iop.org/1751-8121/
U6  - https://doi.org/10.1088/1751-8113/43/14/145304
SN  - 1751-8113
ER  - 
TY  - JOUR
A1  - Haakh, Harald Richard
A1  - Intravaia, Francesco
A1  - Henkel, Carsten
T1  - Temperature dependence of the plasmonic Casimir interaction
N2  - We investigate the role of surface plasmons in the electromagnetic Casimir effect at finite temperature, including situations out of global thermal equilibrium. The free energy is calculated analytically and expanded for different regimes of distances and temperatures. Similar to the zero-temperature case, the interaction changes from attraction to repulsion with distance. Thermal effects are shown to be negligible for small plate separations and at room temperature but become dominant and repulsive at large values of these parameters. In configurations out of global thermal equilibrium, we show that the selective excitation of surface plasmons can create a repulsive Casimir force between metal plates.
Y1  - 2010
UR  - http://pra.aps.org/
U6  - https://doi.org/10.1103/Physreva.82.012507
SN  - 1050-2947
ER  -