350 research outputs found
A one-channel conductor in an ohmic environment: mapping to a TLL and full counting statistics
It is shown that a one-channel mesoscopic conductor in an ohmic environment
can be mapped to the problem of a backscattering impurity in a
Tomonaga-Luttinger liquid (TLL). This allows to determine non perturbatively
the effect of the environment on curves, and to find an exact
relationship between dynamic Coulomb blockade and shot noise. We investigate
critically how this relationship compares to recent proposals in the
literature. The full counting statistics is determined at zero temperature.Comment: 5 pages, 2 figures, shortened version for publication in Phys. Rev.
Let
Transport properties of single atoms
We present a systematic study of the ballistic electron conductance through
sp and 3d transition metal atoms attached to copper and palladium crystalline
electrodes. We employ the 'ab initio' screened Korringa-Kohn-Rostoker Green's
function method to calculate the electronic structure of nanocontacts while the
ballistic transmission and conductance eigenchannels were obtained by means of
the Kubo approach as formulated by Baranger and Stone. We demonstrate that the
conductance of the systems is mainly determined by the electronic properties of
the atom bridging the macroscopic leads. We classify the conducting
eigenchannels according to the atomic orbitals of the contact atom and the
irreducible representations of the symmetry point group of the system that
leads to the microscopic understanding of the conductance. We show that if
impurity resonances in the density of states of the contact atom appear at the
Fermi energy, additional channels of appropriate symmetry could open. On the
other hand the transmission of the existing channels could be blocked by
impurity scattering.Comment: RevTEX4, 9 pages, 9 figure
Dynamical Coulomb blockade of multiple Andreev reflections
We analyze the dynamical Coulomb blockade of multiple Andreev reflections
(MAR) in a superconducting quantum point contact coupled to a macroscopic
impedance. We find that at very low transmission the blockade scales as
with , where is the bias voltage and is the
superconducting gap, as it would correspond to the occurrence of "shots" of
charge . For higher transmission the blockade is reduced both due to Pauli
principle and to elastic renormalization of the MAR probability, and for
certain voltage regions it may even become an "antiblockade", i.e. the current
is enhanced due to the coupling with the electromagnetic environment.Comment: 5 pages, 4 figures, submitted to Phys. Rev. Let
Experimental Test of the Dynamical Coulomb Blockade Theory for Short Coherent Conductors
We observed the recently predicted quantum suppression of dynamical Coulomb
blockade on short coherent conductors by measuring the conductance of a quantum
point contact embedded in a tunable on-chip circuit. Taking advantage of the
circuit modularity we measured most parameters used by the theory. This allowed
us to perform a reliable and quantitative experimental test of the theory.
Dynamical Coulomb blockade corrections, probed up to the second conductance
plateau of the quantum point contact, are found to be accurately normalized by
the same Fano factor as quantum shot noise, in excellent agreement with the
theoretical predictions.Comment: 4 pages, 4 figures, accepted for publication in Physical Review
Letter
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WASTE PACKAGE TRANSPORTER DESIGN
The purpose of this Design Analysis is to develop preliminary design of the waste package transporter used for waste package (WP) transport and related functions in the subsurface repository. This analysis refines the conceptual design that was started in Phase I of the Viability Assessment. This analysis supports the development of a reliable emplacement concept and a retrieval concept for license application design. The scope of this analysis includes the following activities: (1) Assess features of the transporter design and evaluate alternative design solutions for mechanical components. (2) Develop mechanical equipment details for the transporter. (3) Prepare a preliminary structural evaluation for the transporter. (4) Identify and recommend the equipment design for waste package transport and related functions. (5) Investigate transport equipment interface tolerances. This analysis supports the development of the waste package transporter for the transport, emplacement, and retrieval of packaged radioactive waste forms in the subsurface repository. Once the waste containers are closed and accepted, the packaged radioactive waste forms are termed waste packages (WP). This terminology was finalized as this analysis neared completion; therefore, the term disposal container is used in several references (i.e., the System Description Document (SDD)) (Ref. 5.6). In this analysis and the applicable reference documents, the term ''disposal container'' is synonymous with ''waste package''
Inelastic Interaction Corrections and Universal Relations for Full Counting Statistics
We analyze in detail the interaction correction to Full Counting Statistics
(FCS) of electron transfer in a quantum contact originating from the
electromagnetic environment surrounding the contact. The correction can be
presented as a sum of two terms, corresponding to elastic/inelastic electron
transfer. Here we primarily focus on the inelastic correction.
For our analysis, it is important to understand more general -- universal --
relations imposed on FCS only by quantum mechanics and statistics with no
regard for a concrete realization of a contact. So we derive and analyze these
relations. We reveal that for FCS the universal relations can be presented in a
form of detailed balance. We also present several useful formulas for the
cumulants.
To facilitate the experimental observation of the effect, we evaluate
cumulants of FCS at finite voltage and temperature. Several analytical results
obtained are supplemented by numerical calculations for the first three
cumulants at various transmission eigenvalues.Comment: 10 pages, 3 figure
Proposed treatment strategy for reactive hypoglycaemia
Background/aim: Managing reactive hypoglycaemia (RH) poses challenges due to limited and often ineffective treatment options. We report a case series and draw on this to propose a stepwise treatment approach consisting of lifestyle modifications, metformin, GLP-1 analogues, and the use of flash glucose monitoring technology. Method: A retrospective review was conducted to analyse the management of 11 cases presenting with recurrent RH symptoms. Result: Two patients experienced successful resolution of symptoms through lifestyle modifications. Metformin alone was effective in treating seven out of nine patients who received pharmacological treatment. Two patients with previous upper gastrointestinal surgery showed a partial response to metformin and benefited further from additional long-acting GLP-1 analogue. Pharmacological intervention led to significant reductions in insulin and C-peptide levels in repeat mixed meal tolerance tests (P-values 0.043 for insulin and 0.006 for C-peptide). Finally, flash glucose monitoring technology was useful in early detection and preventing episodes of hypoglycaemia in one of these patients with persistent symptoms. Conclusion: These findings highlight the potential efficacy of escalated treatment strategies for RH, including the use of metformin, GLP-1 analogues, and flash glucose monitoring technology
An Assessment of the Human Papillomavirus Immunization Knowledge, Practices, and Prevention Among a Cohort of Urban College Students
Human papillomavirus (HPV) is the most common sexually transmitted disease, yet little is known about the college-age knowledge and prevention practices related to HPV. Although sample vaccination rates mirrored national known vaccination rates, a majority of participants did not complete the three dose vaccine schedule. HPV knowledge was similar between males and females while males were more likely to engage in preventative practices. This information can help healthcare providers reinforce vaccination schedule and prevention practices
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