120,382 research outputs found
Two-component Fermi gas with a resonant interaction
We consider a two-component Fermi gas interacting via a Feshbach molecular
state. It is shown that an important energy scale is
where is the Feshbach coupling constant and the mass of the particles.
Only when where is the Fermi
energy can the gas be expected to enter a universal state in the unitarity
limit on the atomic side of the resonance where there are no molecules present.
The universal state is distinct from the molecular gas state on the other side
of the resonance. We furthermore calculate the energy of the gas for this
universal state and our results are related to current experiments on Li
and K.Comment: 4 pages, 2 figure
Generic Black-Box End-to-End Attack Against State of the Art API Call Based Malware Classifiers
In this paper, we present a black-box attack against API call based machine
learning malware classifiers, focusing on generating adversarial sequences
combining API calls and static features (e.g., printable strings) that will be
misclassified by the classifier without affecting the malware functionality. We
show that this attack is effective against many classifiers due to the
transferability principle between RNN variants, feed forward DNNs, and
traditional machine learning classifiers such as SVM. We also implement GADGET,
a software framework to convert any malware binary to a binary undetected by
malware classifiers, using the proposed attack, without access to the malware
source code.Comment: Accepted as a conference paper at RAID 201
Limits from Weak Gravity Conjecture on Dark Energy Models
The weak gravity conjecture has been proposed as a criterion to distinguish
the landscape from the swampland in string theory. As an application in
cosmology of this conjecture, we use it to impose theoretical constraint on
parameters of two types of dark energy models. Our analysis indicates that the
Chaplygin-gas-type models realized in quintessence field are in the swampland,
whereas the power-low decay model of the variable cosmological constant can
be viable but the parameters are tightly constrained by the conjecture.Comment: Revtex4, 8 pages, 5 figures; References, minor corrections in
content, and acknowledgement adde
A pseudo-potential analog for zero-range photoassociation and Feshbach resonance
A zero-range approach to atom-molecule coupling is developed in analogy to
the Fermi-Huang pseudo-potential treatment of atom-atom interactions. It is
shown by explicit comparison to an exactly-solvable finite-range model that
replacing the molecular bound-state wavefunction with a regularized
delta-function can reproduce the exact scattering amplitude in the
long-wavelength limit. Using this approach we find an analytical solution to
the two-channel Feshbach resonance problem for two atoms in a spherical
harmonic trap
Second-order equation of state with the full Skyrme interaction: toward new effective interactions for beyond mean-field models
In a quantum Fermi system the energy per particle calculated at the second
order beyond the mean-field approximation diverges if a zero-range interaction
is employed. We have previously analyzed this problem in symmetric nuclear
matter by using a simplified nuclear Skyrme interaction, and proposed a
strategy to treat such a divergence. In the present work, we extend the same
strategy to the case of the full nuclear Skyrme interaction. Moreover we show
that, in spite of the strong divergence ( , where is
the momentum cutoff) related to the velocity-dependent terms of the
interaction, the adopted cutoff regularization can be always simultaneously
performed for both symmetric and nuclear matter with different
neutron-to-proton ratio. This paves the way to applications to finite nuclei.Comment: 15 figure
The trispectrum in ghost inflation
We calculate the trispectrum in ghost inflation where both the contact
diagram and scale-exchange diagram are taken into account. The shape of
trispectrum is discussed carefully and we find that the local form is absent in
ghost inflation. In general, for the non-local shape trispectrum there are not
analogous parameters to and which can
completely characterize the size of local form trispectrum.Comment: 19 pages, 8 figures; clarifications and corrections added, version
accepted for publication in JCA
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