1,600 research outputs found
The general structure of quantum resource theories
In recent years it was recognized that properties of physical systems such as
entanglement, athermality, and asymmetry, can be viewed as resources for
important tasks in quantum information, thermodynamics, and other areas of
physics. This recognition followed by the development of specific quantum
resource theories (QRTs), such as entanglement theory, determining how quantum
states that cannot be prepared under certain restrictions may be manipulated
and used to circumvent the restrictions. Here we discuss the general structure
of QRTs, and show that under a few assumptions (such as convexity of the set of
free states), a QRT is asymptotically reversible if its set of allowed
operations is maximal; that is, if the allowed operations are the set of all
operations that do not generate (asymptotically) a resource. In this case, the
asymptotic conversion rate is given in terms of the regularized relative
entropy of a resource which is the unique measure/quantifier of the resource in
the asymptotic limit of many copies of the state. This measure also equals the
smoothed version of the logarithmic robustness of the resource.Comment: 5 pages, no figures, few references added, published versio
Data driving the top quark forward--backward asymmetry with a lepton-based handle
We propose that, within the standard model, the correlation between the
forward--backward asymmetry and the corresponding
lepton-based asymmetry -- at the differential level -- is strong and
rather clean both theoretically and experimentally. Hence a combined
measurement of the two distributions as a function of the lepton , a
direct and experimentally clean observable, would lead to a potentially
unbiased and normalization-free test of the standard model prediction. To check
the robustness of our proposal we study how the correlation is affected by
mis-measurement of the system transverse momenta, acceptance cuts,
scale dependence and compare the results of MCFM, POWHEG (with & without PYTHIA
showering), and SHERPA's CSSHOWER in first-emission mode. We find that the
shape of the relative differential distribution is only moderately distorted hence supporting the
usefulness of our proposal. Beyond the first emission, we find that the
correlation is not accurately captured by lowest-order treatment. We also
briefly consider other differential variables such as the system transverse
mass and the canonical invariant mass. Finally, we study new physics
scenarios where the correlation is significantly distorted and therefore can be
more readily constrained or discovered using our method.Comment: 27 pages, 12 figure
An Exclusive Window onto Higgs Yukawa Couplings
We show that both flavor-conserving and flavor-violating Yukawa couplings of
the Higgs boson to first- and second-generation quarks can be probed by
measuring rare decays of the form h->MV, where M denotes a vector meson and V
indicates either gamma, W or Z. We calculate the branching ratios for these
processes in both the Standard Model and its possible extensions. We discuss
the experimental prospects for their observation. The possibility of accessing
these Higgs couplings appears to be unique to the high-luminosity LHC and
future hadron colliders, providing further motivation for those machines.Comment: 6 pages, 2 figures, 1 tabl
Time-reversal frameness and superselection
We show that appropriate superpositions of motional states are a reference
frame resource that enables breaking of time -reversal superselection so that
two parties lacking knowledge about the other's direction of time can still
communicate. We identify the time-reversal reference frame resource states and
determine the corresponding frameness monotone, which connects time-reversal
frameness to entanglement. In contradistinction to other studies of reference
frame quantum resources, this is the first analysis that involves an
antiunitary rather than unitary representation.Comment: 10 p
B-factory Signals for a Warped Extra Dimension
We study predictions for B-physics in a class of models, recently introduced,
with a non-supersymmetric warped extra dimension. In these models few () TeV Kaluza-Klein masses are consistent with electroweak data due to bulk
custodial symmetry. Furthermore, there is an analog of GIM mechanism which is
violated by the heavy top quark (just as in SM) leading to striking signals at
-factories:(i) New Physics (NP) contributions to transitions
are comparable to SM. This implies that, within this NP framework, the success
of SM unitarity triangle fit is a ``coincidence'' Thus, clean extractions of
unitarity angles via e.g. are likely to
be affected, in addition to O(1) deviation from SM prediction in mixing.
(ii) O(1) deviation from SM predictions for in rate as well
as in forward-backward and direct CP asymmetry. (iii) Large mixing-induced CP
asymmetry in radiative B decays, wherein the SM unamibgously predicts very
small asymmetries. Also with KK masses 3 TeV or less, and with anarchic Yukawa
masses, contributions to electric dipole moments of the neutron are roughly 20
times larger than the current experimental bound so that this framework has a
"CP problem".Comment: On further consideration, we found that our framework does have a "CP
problem" in that though contributions to neutron's electric dipole moment
from CKM-like phases vanish at the one-loop level, sizeable contributions are
induced by Majorana-like phases. Last sentence of abstract is changed along
with para #3 and 4 on page
Measurement of transparency ratios for protons from short-range correlated pairs
Nuclear transparency, Tp(A), is a measure of the average probability for a
struck proton to escape the nucleus without significant re-interaction.
Previously, nuclear transparencies were extructed for quasi-elastic A(e,e'p)
knockout of protons with momentum below the Fermi momentum, where the spectral
functions are well known. In this paper we extract a novel observable, the
transparency ratio, Tp(A)/T_p(12C), for knockout of high-missing-momentum
protons from the breakup of short range correlated pairs (2N-SRC) in Al, Fe and
Pb nuclei relative to C. The ratios were measured at momentum transfer Q^2 >
1.5 (GeV/c)^2 and x_B > 1.2 where the reaction is expected to be dominated by
electron scattering from 2N-SRC. The transparency ratios of the knocked-out
protons coming from 2N-SRC breakup are 20 - 30% lower than those of previous
results for low missing momentum. They agree with Glauber calculations and
agree with renormalization of the previously published transparencies as
proposed by recent theoretical investigations. The new transparencies scale as
A^-1/3, which is consistent with dominance of scattering from nucleons at the
nuclear surface.Comment: 6 pages, 4 figure
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