1,045 research outputs found
Anyons and the Bose-Fermi duality in the finite-temperature Thirring model
Solutions to the Thirring model are constructed in the framework of algebraic
QFT. It is shown that for all positive temperatures there are fermionic
solutions only if the coupling constant is . These fermions are inequivalent and only for they are canonical
fields. In the general case solutions are anyons. Different anyons (which are
uncountably many) live in orthogonal spaces and obey dynamical equations (of
the type of Heisenberg's "Urgleichung") characterized by the corresponding
values of the statistic parameter. Thus statistic parameter turns out to be
related to the coupling constant and the whole Hilbert space becomes
non-separable with a different "Urgleichung" satisfied in each of its sectors.
This feature certainly cannot be seen by any power expansion in .
Moreover, since the latter is tied to the statistic parameter, it is clear that
such an expansion is doomed to failure and will never reveal the true structure
of the theory.
The correlation functions in the temperature state for the canonical dressed
fermions are shown by us to coincide with the ones for bare fields, that is in
agreement with the uniqueness of the -KMS state over the CAR algebra
( being the shift automorphism). Also the -anyon two-point
function is evaluated and for scalar field it reproduces the result that is
known from the literature.Comment: 25 pages, LaTe
On Supergroups with Odd Clifford Parameters and Supersymmetry with Modified Leibniz Rule
We investigate supergroups with Grassmann parameters replaced by odd Clifford
parameters. The connection with non-anticommutative supersymmetry is discussed.
A Berezin-like calculus for odd Clifford variables is introduced. Fermionic
covariant derivatives for supergroups with odd Clifford variables are derived.
Applications to supersymmetric quantum mechanics are made. Deformations of the
original supersymmetric theories are encountered when the fermionic covariant
derivatives do not obey the graded Leibniz property. The simplest non-trivial
example is given by the N=2 SQM with a real multiplet and a cubic
potential. The action is real. Depending on the overall sign ("Euclidean" or
"Lorentzian") of the deformation, a Bender-Boettcher pseudo-hermitian
hamiltonian is encountered when solving the equation of motion of the auxiliary
field. A possible connection of our framework with the Drinfeld twist
deformation of supersymmetry is pointed out.Comment: Final version to be published in Int. J. Mod. Phys. A; 20 page
β decay of semi-magic 130Cd: Revision and extension of the level scheme of 130 In
A. Jungclaus et al.; 8 págs.; 5 figs.; 3 tabs.The β decay of the semi-magic nucleus Cd130 has been studied at the RIBF facility at the RIKEN Nishina Center. The high statistics of the present experiment allowed for a revision of the established level scheme of In130 and the observation of additional β feeding to high-lying core-excited states in In130. The experimental results are compared to shell-model calculations employing a model space consisting of the full major N=50-82 neutron and Z=28-50 proton shells and the NA-14 interaction, and good agreement is found. ©2016 American Physical SocietyWe thank the staff of the RIKEN Nishina Center accelerator
complex for providing stable beams with high intensities
to the experiment. We acknowledge the EUROBALL
Owners Committee for the loan of germanium detectors
and the PreSpec Collaboration for the readout electronics
of the cluster detectors. This work was supported by the
Spanish Ministerio de Ciencia e Innovación under contract
FPA2011-29854-C04 and the Spanish Ministerio de Economía
y Competitividad under Contract No. FPA2014-57196-C5-
4-P, the Generalitat Valenciana (Spain) under Grant No.
PROMETEO/2010/101, the National Research Foundation of
Korea (NRF) grant funded by the Korea government (MEST)
(NRF-2014S1A2A2028636, 2016K1A3A7A09005579), the
Priority Centers Research Program in Korea (2009-0093817),
OTKA Contract No. K-100835, JSPS KAKENHI (Grant No.
25247045), the European Commission through the Marie
Curie Actions call FP7-PEOPLE-2011-IEF under Contract
No. 300096, the US Department of Energy, Office of Nuclear
Physics, under Contract No.DE-AC02-06CH11357, the STFC
(UK), the “RIKEN foreign research program,” the German
BMBF (No. 05P12RDCIA, No. 05P12RDNUP, and No.
05P12PKFNE), HIC for FAIR, the DFG cluster of excellence
“Origin and Structure of the Universe,” and DFG (Contract
No. KR2326/2-1).Peer Reviewe
First observation of γ rays emitted from excited states south-east of Sn132: The πg−19/2⊗νf7/2 multiplet of In83132
A. Jungclaus et al. ; 6 págs.; 4 figs. ; Rapid CommunicationsFor the first time, the γ decay of excited states has been observed in a nucleus situated in the quadrant south-east of doubly magic Sn132, a region in which experimental information so far is limited to ground-state properties. Six γ rays with energies of 50, 86, 103, 227, 357, and 602 keV were observed following the β-delayed neutron emission from Cd85133, populated in the projectile fission of a U238 beam at the Radioactive Isotope Beam Factory at RIKEN within the EURICA project. The new experimental information is compared to the results of a modern realistic shell-model calculation, the first one in this region very far from stability, focusing in particular on the π0g9/2-1 - ν1f7/2 particle-hole multiplet in In83132. In addition, theoretical estimates based on a scaling of the two-body matrix elements for the πh11/2-1 - νg9/2 analog multiplet in Tl127208, one major proton and one major neutron shell above, are presented. ©2016 American Physical SocietyWe thank the staff of the RIKEN Nishina Center accelerator
complex for providing stable beams with high intensities to
the experiment. We acknowledge the EUROBALL Owners
Committee for the loan of germanium detectors and the
PreSpec Collaboration for the readout electronics of the
cluster detectors. This work was supported by the Spanish
Ministerio de Ciencia e Innovación under Contract No.
FPA2011-29854-C04 and the Spanish Ministerio de Economía
y Competitividad under Contract No. FPA2014-57196-C5-
4-P, the Generalitat Valenciana (Spain) under Grant No.
PROMETEO/2010/101, the National Research Foundation of
Korea (NRF) grant funded by the Korea government (MEST)
(No. NRF-2012R1A1A1041763), the Priority Centers Research
Program in Korea (2009-0093817), OTKA Contract
No. K-100835, JSPS KAKENHI (Grant No. 25247045), the
European Commission through the Marie Curie Actions call
PEOPLE-2011FP7-IEF under Contract No. 300096 and the
German BMBF (No. 05P12RDCIA and No. 05P12RDNUP),
and Helmholtz International Center for FAIR.Peer Reviewe
Meson Production in p+d Reactions
The production of neutral and charged pions as well as eta mesons is studied
in the Delta and N* resonance region, respectively. Heavy A=3 recoils were
measured with the GEM detector. The differential cross sections covering the
full angular range are compared with model calculations.Comment: 4 pages, latex, 4 figures, talk presented at the XVIIth European
Conference on Few-Body Problems in Physics, Evora, Portugal, September 2000;
to be published in Nucl. Phys.
Morphological characteristics of motor neurons do not determine their relative susceptibility to degeneration in a mouse model of severe spinal muscular atrophy
Spinal muscular atrophy (SMA) is a leading genetic cause of infant mortality, resulting primarily from the degeneration and loss of lower motor neurons. Studies using mouse models of SMA have revealed widespread heterogeneity in the susceptibility of individual motor neurons to neurodegeneration, but the underlying reasons remain unclear. Data from related motor neuron diseases, such as amyotrophic lateral sclerosis (ALS), suggest that morphological properties of motor neurons may regulate susceptibility: in ALS larger motor units innervating fast-twitch muscles degenerate first. We therefore set out to determine whether intrinsic morphological characteristics of motor neurons influenced their relative vulnerability to SMA. Motor neuron vulnerability was mapped across 10 muscle groups in SMA mice. Neither the position of the muscle in the body, nor the fibre type of the muscle innervated, influenced susceptibility. Morphological properties of vulnerable and disease-resistant motor neurons were then determined from single motor units reconstructed in Thy.1-YFP-H mice. None of the parameters we investigated in healthy young adult mice - including motor unit size, motor unit arbor length, branching patterns, motor endplate size, developmental pruning and numbers of terminal Schwann cells at neuromuscular junctions - correlated with vulnerability. We conclude that morphological characteristics of motor neurons are not a major determinant of disease-susceptibility in SMA, in stark contrast to related forms of motor neuron disease such as ALS. This suggests that subtle molecular differences between motor neurons, or extrinsic factors arising from other cell types, are more likely to determine relative susceptibility in SMA
Nonlinear Bogolyubov-Valatin transformations and quaternions
In introducing second quantization for fermions, Jordan and Wigner
(1927/1928) observed that the algebra of a single pair of fermion creation and
annihilation operators in quantum mechanics is closely related to the algebra
of quaternions H. For the first time, here we exploit this fact to study
nonlinear Bogolyubov-Valatin transformations (canonical transformations for
fermions) for a single fermionic mode. By means of these transformations, a
class of fermionic Hamiltonians in an external field is related to the standard
Fermi oscillator.Comment: 6 pages REVTEX (v3: two paragraphs appended, minor stylistic changes,
eq. (39) corrected, references [10]-[14], [36], [37], [41], [67]-[69] added;
v4: few extensions, references [62], [63] added, final version to be
published in J. Phys. A: Math. Gen.
Comparative study of soil test methods for determination of plant available potassium in Bulgarian arable soils
This comparative study was aimed at estimating analytical behavior of methods for determination of plant available potassium applied to Bulgarian arable soils and to reveal the relationship between the amount of extractable K. Twenty-four samples from two traditional agricultural regions in Bulgaria were studied. Soil potassium was extracted by NH4OAc/HOAc pH 4.5 (AA), diluted double acid (Mehlich 1), CaCl2, BaCl2 and a modified acetate/lactate method (ALM) and determined by Flame AES. The factors influencing the methods accuracy were identified and uncertainty was estimated. The expanded uncertainty was (in mg K2O (100 g dry soil)-1): 0.10 (ALM), 0.64 (Mehlich 1), 0.17 (CaCl2) and 1.1 (AA). The study revealed that the factor which mainly influence the uncertainty of the applied analytical methods for plant available potassium in soil was the calibration of Flame AES determination. The obtained results showed that extractable potassium lowered in the following order K ALM ≥ K AA > K M ehlich 1> K BaCl2> K CaCl2 . Soil potassium extracted by ALM procedure correlated with AA, BaCl2-K, CaCl2 -K and Mehlich 1 - K at 0.05 level of significance. ALM extracted between 1.2 to 5.8 times more soil K than other methods did. The obtained results provided a base for further study on correlation between extractable K and soil fertility indices for particular soil types and climatic regions in Bulgaria.The authors of this study were thankful to prof. Margarita Nikolova for the idea and discussions; to Mr. Vencislav Nekov (Sembodja, Ltd., Sofia, Bulgaria) for providing soil samples. Lyudmila Angelova acknowledged the financial support of the National Program for Support of Young Researchers 2018–2020 funded by the Bulgarian Ministry of Education and Science. The authors are thankful to Ms. Yulia Ivanova for making some of the laboratory experiments
Measurement of p + d -> 3He + eta in S(11) Resonance
We have measured the reaction p + d -> 3He + eta at a proton beam energy of
980 MeV, which is 88.5 MeV above threshold using the new ``germanium wall''
detector system. A missing--mass resolution of the detector system of 2.6% was
achieved. The angular distribution of the meson is forward peaked. We found a
total cross section of (573 +- 83(stat.) +- 69(syst.))nb. The excitation
function for the present reaction is described by a Breit Wigner form with
parameters from photoproduction.Comment: 8 pages, 2 figures, corrected typos in heade
- …