304 research outputs found
The Risk-Taking Channel and Monetary Transmission Mechanism in Colombia
The recent financial crisis has brought to the forefront the need of a better understanding of the transmission mechanisms of monetary policy. The main step forward in this direction has drawn on work aimed at stressing the role of the financial sector in this transmission. Particular emphasis has been place on how policy actions impact risk perceptions and attitudes of banks and other financial institutions, leading to shifts in the supply of credit. Along these lines, and based on evidence from Colombia, the present paper finds a significant link between low interest rates and banksâ risk taking based on evidence from Colombia. Lower interest rates raise the probability of default on new loans but reduce that on outstanding loans. Furthermore, this channel of policy transmission depends on some bank, loan and borrower characteristics, as well on macroeconomic conditions such as the rate of growth of the economy.Monetary policy, lending standards, risk taking, duration analysis, accelerated failure time models. Classification JEL: E44, G21, L14
Multipartite Entanglement Generation Assisted by Inhomogeneous Coupling
We show that controllable inhomogeneous coupling between two-level systems
and a common data bus provides a fast mechanism to produce multipartite
entanglement. Our proposal combines resonant interactions and engineering of
coupling strengths---between the qubits and the single mode---leading to well
defined entangled states. Furthermore, we show that, if the two-level systems
interact dispersively with the quantized mode, engineering of coupling
strengths allows the controlled access of the symmetric Hilbert space of
qubits.Comment: 5 pages, 4 figures. Submitted for publicatio
Sudden Birth Versus Sudden Death of Entanglement in Multipartite Systems
We study the entanglement dynamics of two cavities interacting with
independent reservoirs. Expectedly, we observe that, as the cavity entanglement
is depleted, it is transferred to the reservoir degrees of freedom. We find
that when the cavity entanglement suddenly disappear, the reservoir
entanglement suddenly and necessarily appears. Surprisingly, we show that this
{\it entanglement sudden birth} can manifest before, simultaneously, or even
after {\it entanglement sudden death}. Finally, we present an explanatory study
of other entanglement partitions and of higher dimensional systems.Comment: 5 pages, 5 figures, accepted for publication in Physical Review
Letter
Tripartite entanglement in quantum memristors
We study the entanglement and memristive properties of three coupled quantum
memristors. We consider quantum memristors based on superconducting asymmetric
SQUID architectures which are coupled via inductors. The three quantum
memristors are arranged in two different geometries: linear and triangular
coupling configurations. We obtain a variety of correlation measures, including
bipartite entanglement and tripartite negativity. We find that, for identical
quantum memristors, entanglement and memristivity follow the same behavior for
the triangular case and the opposite one in the linear case. Finally, we study
the multipartite correlations with the tripartite negativity and entanglement
monogamy relations, showing that our system has genuine tripartite
entanglement. Our results show that quantum correlations in multipartite
memristive systems have a non-trivial role and can be used to design quantum
memristor arrays for quantum neural networks and neuromorphic quantum computing
architectures.Comment: 9 pages, 6 figure
Microwave Quantum Memristors
We propose a design of a superconducting quantum memristive device in the
microwave regime, that is, a microwave quantum memristor. It comprises two
linked resonators, where the primary one is coupled to a superconducting
quantum interference device (SQUID), allowing the adjustment of the resonator
properties with an external magnetic flux. The auxiliary resonator is operated
through weak measurements, providing feedback to the primary resonator via the
SQUID and establishing stable memristive behavior via the external magnetic
flux. The device operates with a classical input signal in one cavity while
reading the response in the other, serving as a fundamental building block for
arrays of microwave quantum memristors. In this sense, we observe that a
bipartite setup can retain its memristive behavior while gaining entanglement
and quantum correlations. Our findings open the door to the experimental
implementation of memristive superconducting quantum devices and arrays of
microwave quantum memristors on the path to neuromorphic quantum computing.Comment: 9+6 pages, 10 figure
Low Cost Semi Automated Assembly Unit for Small Size Back Contact Modules and Low Cost Interconnection Approach
AbstractWe present our low cost assembly unit to manufacture back contact solar modules based on the conductive backsheet (CBS) approach. This in house developed apparatus was built to assemble test modules containing one up to four 6 inch back contact solar cells. The system is a retrofit of a commercially available CNC system which is equipped with a cell grabber and a manual dispensing system (by Nordson). The total cost of the setup was roughly 4000 ⏠excluding the dispenser unit. Using this equipment we assembled several small size modules containing one and four Zebra cells, which are low cost 6 inch IBC solar cells developed at ISC Konstanz [1,2]. The contact between copper backsheet and back contact cell of the one cell modules we present here is formed by low temperature solder paste (LTSP). First cell to module (CTM) loss evaluations and reliability results suggest that this material could be a viable alternative to electrically conductive adhesive (ECA) which is currently the most commonly used material for this purpose
The LAEX and NASA portals for CoRoT public data
* Aims. We describe here the main functionalities of the LAEX (Laboratorio de
Astrofisica Estelar y Exoplanetas/Laboratory for Stellar Astrophysics and
Exoplanets) and NASA portals for CoRoT Public Data. The CoRoT archive at LAEX
was opened to the community in January 2009 and is managed in the framework of
the Spanish Virtual Observatory. NStED (NASA Star and Exoplanet Database)
serves as the CoRoT portal for the US astronomical community. NStED is a
general purpose stellar and exoplanet archive with the aim of providing support
for NASA planet finding and characterisation goals, and the planning and
support of NASA and other space missions. CoRoT data at LAEX and NStED can be
accessed at http://sdc.laeff.inta.es/corotfa/ and
http://nsted.ipac.caltech.edu,respectively.
* Methods. Based on considerable experience with astronomical archives, the
aforementioned archives are designed with the aim of delivering science-quality
data in a simple and efficient way.
* Results. LAEX and NStED not only provide access to CoRoT Public Data but
furthermore serve a variety of observed and calculated astrophysical data. In
particular, NStED provides scientifically validated information on stellar and
planetary data related to the search for and characterization of extrasolar
planets, and LAEX makes any information from Virtual Observatory services
available to the astronomical community.Comment: Accepted for publication in Astronomy & Astrophysic
Determination of the high-pressure crystal structure of BaWO4 and PbWO4
We report the results of both angle-dispersive x-ray diffraction and x-ray
absorption near-edge structure studies in BaWO4 and PbWO4 at pressures of up to
56 GPa and 24 GPa, respectively. BaWO4 is found to undergo a pressure-driven
phase transition at 7.1 GPa from the tetragonal scheelite structure (which is
stable under normal conditions) to the monoclinic fergusonite structure whereas
the same transition takes place in PbWO4 at 9 GPa. We observe a second
transition to another monoclinic structure which we identify as that of the
isostructural phases BaWO4-II and PbWO4-III (space group P21/n). We have also
performed ab initio total energy calculations which support the stability of
this structure at high pressures in both compounds. The theoretical
calculations further find that upon increase of pressure the scheelite phases
become locally unstable and transform displacively into the fergusonite
structure. The fergusonite structure is however metastable and can only occur
if the transition to the P21/n phases were kinetically inhibited. Our
experiments in BaWO4 indicate that it becomes amorphous beyond 47 GPa.Comment: 46 pages, 11 figures, 3 table
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