arXiv subjects

Daniel Golubchik

Publications and source records attributed to Daniel Golubchik.

4 recordsLinked to original sources

arXiv2011

Measurement of the vortex mass in a superconducting film

We have combined high resolution magneto-optical imaging with an ultra-fast heating/cooling technique to measure the movement of individual vortices in a superconducting film. The motion took place while the film was heated close to $T_c$, where pinning and viscous forces are relatively small. Under these conditions, vortices move due to the magnetic repulsion between them. We found that a finite vortex mass has to be included in the analysis in order to account for the experimental results. The extent of the motion is consistent with a vortex mass being 3 orders of magnitude smaller than the mass of all the electrons in the core.

cond-mat.supr-con↗

arXiv2011

Experimental determination of correlations between spontaneously formed vortices in a superconductor

We have imaged spontaneously created arrays of vortices (magnetic flux quanta), generated in a superconducting film quenched through its transition temperature at rates around $10^9 K/s$. From these images, we calculated the positional correlation functions for two vortices and for 3 vortices. We compared our results with simulations of the time dependent Ginzburg Landau equation in 2D. The results are in agreement with the Kibble-Zurek scenario of spontaneous vortex creation. In addition, the correlation functions are insensitive to the presence of a gauge field.

cond-mat.stat-mech↗

arXiv2009

Correlations beyond the horizon

We have imaged spontaneously created arrays of vortices (magnetic flux quanta), generated in a superconducting film quenched through its transition temperature at rates around $10^9 K/s$. Spontaneous appearance of vortices is predicted by Kibble-Zurek and by Hindmarsh-Rajantie models of phase transitions under non-equilibrium conditions. Differentiating between these models requires a measurement of the internal correlations within the emerging vortex array. In addition to short range correlations predicted by Kibble and Zurek, we found unexpected long range correlations which are not described by any of the existing models.

cond-mat.supr-con↗

arXiv2006

Dependence of Dripping on the Orifice Diameter in a Leaky Faucet

We report the results of experiments that examined the dependence of the dripping dynamics of a leaky faucet on the orifice diameter. The transition of the dripping frequency between periodic and chaotic states was found to depend on the orifice diameter. We suggest a theoretical explanation for these transitions based on drop formation time scales. In addition, short-range anti-correlations were measured in the chaotic region. These too showed a dependence on the faucet diameter. Finally, a comparison was done between the experimental results with a one-dimensional model for drop formation. Quantitative agreement was found between the simulations and the experimental results.

physics.flu-dyn↗