3,077 research outputs found
Bose-Einstein Condensation in a Constant Magnetic Field
We discuss the occurrence of Bose-Einstein condensation in systems of
noninteracting charged particles in three in one dimensions and in presence of
an external magnetic field. In the one dimensional, as well as in the magnetic
field cases, although not a critical temperature, a characteristic temperature
can be found, corresponding to the case in which the ground state density
becomes a macroscopic fraction of the total density. The case of relativistic
charged scalar and vector particles is studied. The results obtainedgive
support to the existence of superconductivity in extremely strong magnetic
fields, and leads to the prediction of superconductive-ferromagnetic behavior
in the vector field case, which might be of interest in condensed matter as
well as in cosmology. Some features of the magnetization in the early universe
are conjectured.Comment: 20 pages, 2 GIF figure
Labor Rights and Foreign Direct Investment in Latin America: The Empirical Analysis of Proximity Hypothesis
What impact do labor rights practices have on foreign direct investment (FDI) in Latin America? While existing research shows how participation in the global production network influences host countryâs labor standards, few studies delve into reversed causal mechanisms whereby changes in labor standards affects FDI inflows. While conventional wisdom says protection of labor rights has negative influence on FDI, I argue that for Latin American countries, practical protection of labor rights attracts FDI. Practical protection of labor right acts as a proxy and signals that host government could protect foreign assets that are under the risk of expropriation. I expect practical increase in labor rights positively affects FDI over time. Utilizing data of 30 Latin American countries and 128 non-Latin American developing countries from 1994 to 2012, and an error correction model shows that de facto labor rights protection has a long-term effect on foreign direct investment in Latin America
Observation of fractional quantum Hall effect in an InAs quantum well
The two-dimensional electron system in an InAs quantum well has emerged as a
prime candidate for hosting exotic quasi-particles with non-Abelian statistics
such as Majorana fermions and parafermions. To attain its full promise,
however, the electron system has to be clean enough to exhibit
electron-electron interaction phenomena. Here we report the observation of
fractional quantum Hall effect in a very low disorder InAs quantum well with a
well-width of 24 nm, containing a two-dimensional electron system with a
density cm and low-temperature mobility cm/Vs. At a temperature of mK and T, we
observe a deep minimum in the longitudinal resistance, accompanied by a nearly
quantized Hall plateau at Landau level filling factor
Climate-driven changes in life-history traits of the bastard grunt (Pomadasys incisus) in the north-western Mediterranean
This study evaluates the influence of sea water temperature on the life-history traits of the thermophilic bastard grunt Pomadasys incisus in the Catalan coast. We compared two key traits of this species, condition and reproduction, from populations in two separate areas with different thermal regimes: the Gulf of Roses (cold area) and the Ebre Delta (warm area). Specimens were collected monthly from each area between 2010 and 2012. The results were also compared with those given in the literature from sites where the species is more common, i.e. the southern Mediterranean and eastern Atlantic. Our findings indicate that, compared to the populations in warmer environments, the population inhabiting the colder waters appears to be in significantly poorer condition and there is some deviance in their life-history traits: egg size and quality being traded-off for higher egg numbers; lower lengths at maturity and alterations to spawning phenology. A certain degree of plasticity in life-history traits may favour the process of expansion and establishment of this thermophilic species into newly available but colder habitats of the north-western Mediterranean under a scenario of climate change
Mechanism for flux guidance by micrometric antidot arrays in superconducting films
A study of magnetic flux penetration in a superconducting film patterned with
arrays of micron sized antidots (microholes) is reported. Magneto-optical
imaging (MOI) of a YBCO film shaped as a long strip with perpendicular antidot
arrays revealed both strong guidance of flux, and at the same time large
perturbations of the overall flux penetration and flow of current. These
results are compared with a numerical flux creep simulation of a thin
superconductor with the same antidot pattern. To perform calculations on such a
complex geometry, an efficient numerical scheme for handling the boundary
conditions of the antidots and the nonlocal electrodynamics was developed. The
simulations reproduce essentially all features of the MOI results. In addition,
the numerical results give insight into all other key quantities, e.g., the
electrical field, which becomes extremely large in the narrow channels
connecting the antidots.Comment: 8 pages, 7 figure
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