2,096 research outputs found
Two- and Three-particle States in a Nonrelativistic Four-fermion Model in the Fine-tuning Renormalization Scheme. Goldstone mode "against" extension theory
In a nonrelativistic contact four-fermion model we show that simple
regularisation prescriptions together with a definite fine-tuning of the
cut-off-parameter dependence of ``bare'' quantities give the exact solutions
for the two-particle sector and Goldstone modes. Their correspondence with the
self-adjoint extension into Pontryagin space is established leading to
self-adjoint semi-bounded Hamiltonians in three-particle sectors as well.
Renormalized Faddeev equations for the bound states with Fredholm properties
are obtained and analysed.Comment: 23 pages, LaTeX, changed content, added references and two figures,
to appear in the Few Body System
Neutrino-nucleon cross sections at energies of Megaton-scale detectors
An updated set of (anti)neutrino-nucleon charged and neutral current cross
sections at is presented.
These cross sections are of particular interest for the detector optimization
and data processing and interpretation in the future Megaton-scale experiments
like PINGU, ORCA, and Hyper-Kamiokande. Finite masses of charged leptons and
target mass corrections in exclusive and deep inelastic
interactions are taken into account. A new set of QCD NNLO parton density
functions, the ABMP15, is used for calculation of the DIS cross sections. The
sensitivity of the cross sections to phenomenological parameters and to
extrapolations of the nucleon structure functions to small and is
studied. An agreement within the uncertainties of our calculations with
experimental data is demonstrated.Comment: 4 pages, 4 figures, accepted for the VLVnT-2015 Conference
proceedings, will be published on EPJ Web of Conference
Number-theory renormalization of vacuum energy
For QFT on a lattice of dimension d>=3, the vacuum energy (both bosonic and
fermionic) is zero if the Hamiltonian is a function of the square of the
momentum, and the calculation of the vacuum energy is performed in the ring of
residue classes modulo N. This fact is related to a problem from number theory
about the number of ways to represent a number as a sum of squares in the
ring of residue classes modulo N.Comment: 33 pages, 7 figure
Electric Current and Noise in Long GaN Nanowires in the Space-Charge Limited Transport Regime
We studied electric current and noise in planar GaN nanowires (NWs). The
results obtained at low voltages provide us with estimates of the depletion
effects in the NWs. For larger voltages, we observed the space-charge limited
current (SCLC) effect. The onset of the effect clearly correlates with the NW
width. For narrow NWs the mature SCLC regime was achieved. This effect has
great impact on fluctuation characteristics of studied NWs. At low voltages, we
found that the normalized noise level increases with decreasing NW width. In
the SCLC regime, a further increase in the normalized noise intensity (up to
1E4 times) was observed, as well as a change in the shape of the spectra with a
tendency towards slope -3/2. We suggest that the features of the electric
current and noise found in the NWs are of a general character and will have an
impact on the development of NW-based devices.Comment: 12 pages, 4 figures in Fluctuation and Noise Letters (2017
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