75,730 research outputs found
Answering Mermin's Challenge with Conservation per No Preferred Reference Frame
In 1981, Mermin published a now famous paper titled, "Bringing home the
atomic world: Quantum mysteries for anybody" that Feynman called, "One of the
most beautiful papers in physics that I know." Therein, he presented the
"Mermin device" that illustrates the conundrum of quantum entanglement per the
Bell spin states for the "general reader." He then challenged the "physicist
reader" to explain the way the device works "in terms meaningful to a general
reader struggling with the dilemma raised by the device." Herein, we show how
"conservation per no preferred reference frame (NPRF)" answers that challenge.
In short, the explicit conservation that obtains for Alice and Bob's
Stern-Gerlach spin measurement outcomes in the same reference frame holds only
on average in different reference frames, not on a trial-by-trial basis. This
conservation is SO(3) invariant in the relevant symmetry plane in real space
per the SU(2) invariance of its corresponding Bell spin state in Hilbert space.
Since NPRF is also responsible for the postulates of special relativity, and
therefore its counterintuitive aspects of time dilation and length contraction,
we see that the symmetry group relating non-relativistic quantum mechanics and
special relativity via their "mysteries" is the restricted Lorentz group.Comment: 18 pages, 9 figures. This version as revised and resubmitted to
Scientific Report
Evolution of the gaps through the cuprate phase-diagram
The actual physical origin of the gap at the antinodes, and a clear
identification of the superconducting gap are fundamental open issues in the
physics of high- superconductors. Here, we present a systematic electronic
Raman scattering study of a mercury-based single layer cuprate, as a function
of both doping level and temperature. On the deeply overdoped side, we show
that the antinodal gap is a true superconducting gap. In contrast, on the
underdoped side, our results reveal the existence of a break point close to
optimal doping below which the antinodal gap is gradually disconnected from
superconductivity. The nature of both the superconducting and normal state is
distinctly different on each side of this breakpoint
Foot-operated cell-counter
Cell-counter for cell indices consists of a footboard with four pressure sensitive switches and an enclosure for the components and circuitry. This device increases the operators efficiency by reducing the number of required hand movements
Exploring Deep Space: Learning Personalized Ranking in a Semantic Space
Recommender systems leverage both content and user interactions to generate
recommendations that fit users' preferences. The recent surge of interest in
deep learning presents new opportunities for exploiting these two sources of
information. To recommend items we propose to first learn a user-independent
high-dimensional semantic space in which items are positioned according to
their substitutability, and then learn a user-specific transformation function
to transform this space into a ranking according to the user's past
preferences. An advantage of the proposed architecture is that it can be used
to effectively recommend items using either content that describes the items or
user-item ratings. We show that this approach significantly outperforms
state-of-the-art recommender systems on the MovieLens 1M dataset.Comment: 6 pages, RecSys 2016 RSDL worksho
The nodal gap component as a good candidate for the superconducting order parameter in cuprates
Although more than twenty years have passed since the discovery of high
temperature cuprate superconductivity, the identification of the
superconducting order parameter is still under debate. Here, we show that the
nodal gap component is the best candidate for the superconducting order
parameter. It scales with the critical temperature over a wide doping
range and displays a significant temperature dependence below in both the
underdoped and the overdoped regimes of the phase diagram. In contrast, the
antinodal gap component does not scale with in the underdoped side and
appears to be controlled by the pseudogap amplitude. Our experiments establish
the existence of two distinct gaps in the underdoped cuprates
Shock statistics in higher-dimensional Burgers turbulence
We conjecture the exact shock statistics in the inviscid decaying Burgers
equation in D>1 dimensions, with a special class of correlated initial
velocities, which reduce to Brownian for D=1. The prediction is based on a
field-theory argument, and receives support from our numerical calculations. We
find that, along any given direction, shocks sizes and locations are
uncorrelated.Comment: 4 pages, 8 figure
Quasiparticle Description of Hot QCD at Finite Quark Chemical Potential
We study the extension of a phenomenologically successful quasiparticle model
that describes lattice results of the equation of state of the deconfined phase
of QCD for Tc <= T < 4 Tc, to finite quark chemical potential mu. The phase
boundary line Tc(mu), the pressure difference (p(T,mu)-p(T,mu=0))/T^4 and the
quark number density nq(T,mu)/T^3 are calculated and compared to recent lattice
results. Good agreement is found up to quark chemical potentials of order mu =
Tc.Comment: 12 pages, 7 figures; added reference
Sub-100 attoseconds optics-to-microwave synchronization
We use two fiber-based femtosecond frequency combs and a low-noise carrier
suppression phase detection system to characterize the optical to microwave
synchronization achievable with such frequency divider systems. By applying
specific noise reduction strategies, a residual phase noise as low as -120
dBc/Hz at 1 Hz offset frequency from a 11.55 GHz carrier is measured. The
fractional frequency instability from a single optical-to-frequency divider is
1.1E-16 at 1 s averaging down to below 2E-19 after only 1000 s. The
corresponding rms time deviation is lower than 100 attoseconds up to 1000 s
averaging duration.Comment: 4 pages, 3 figure
Non equilibrium dynamics of mixing, oscillations and equilibration: a model study
The non-equilibrium dynamics of mixing, oscillations and equilibration is
studied in a field theory of flavored neutral mesons that effectively models
two flavors of mixed neutrinos, in interaction with other mesons that represent
a thermal bath of hadrons or quarks and charged leptons. This model describes
the general features of neutrino mixing and relaxation via charged currents in
a medium. The reduced density matrix and the non-equilibrium effective action
that describes the propagation of neutrinos is obtained by integrating out the
bath degrees of freedom. We obtain the dispersion relations, mixing angles and
relaxation rates of ``neutrino'' quasiparticles. The dispersion relations and
mixing angles are of the same form as those of neutrinos in the medium, and the
relaxation rates are given by where
are the relaxation rates of the flavor fields in
\emph{absence} of mixing, and is the mixing angle in the medium.
A Weisskopf-Wigner approximation that describes the asymptotic time evolution
in terms of a non-hermitian Hamiltonian is derived. At long time
``neutrinos'' equilibrate with the bath. The equilibrium
density matrix is nearly diagonal in the basis of eigenstates of an
\emph{effective Hamiltonian that includes self-energy corrections in the
medium}. The equilibration of ``sterile neutrinos'' via active-sterile mixing
is discussed.Comment: 28 pages, 3 figures, version to appear in PR
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