3,918 research outputs found
Non-equilibrium dynamics of bosonic atoms in optical lattices: Decoherence of many-body states due to spontaneous emission
We analyze in detail the heating of bosonic atoms in an optical lattice due
to incoherent scattering of light from the lasers forming the lattice. Because
atoms scattered into higher bands do not thermalize on the timescale of typical
experiments, this process cannot be described by the total energy increase in
the system alone (which is determined by single-particle effects). The heating
instead involves an important interplay between the atomic physics of the
heating process and the many-body physics of the state. We characterize the
effects on many-body states for various system parameters, where we observe
important differences in the heating for strongly and weakly interacting
regimes, as well as a strong dependence on the sign of the laser detuning from
the excited atomic state. We compute heating rates and changes to
characteristic correlation functions based both on perturbation theory
calculations, and a time-dependent calculation of the dissipative many-body
dynamics. The latter is made possible for 1D systems by combining
time-dependent density matrix renormalization group (t-DMRG) methods with
quantum trajectory techniques.Comment: 17 pages, 14 figure
Human Capital Spillovers, Productivity and Growth in the Manufacturing Sector of Pakistan
Manufacturing is an important sector of Pakistan’s economy. The main focus of this paper is to analyse the major factors of value-added growth and productivity in the manufacturing sector by using Translog Production Technology over the period 1971-72 to 2004-05. The empirical findings show that the contribution of productivity and human capital is around one- third of the total value-added growth in manufacturing sector which is less than the contribution attributed to these factors in developed and many other developing countries. Conventional factors like capital and labour are still the mainstay in the value-added growth of Pakistan’s manufacturing sector.Human Capital Spillovers, Total Factor Productivity, Absolute and Relative Shares
Measuring entanglement growth in quench dynamics of bosons in an optical lattice
We discuss a scheme to measure the many-body entanglement growth during
quench dynamics with bosonic atoms in optical lattices. By making use of a 1D
or 2D setup in which two copies of the same state are prepared, we show how
arbitrary order Renyi entropies can be extracted using tunnel-coupling between
the copies and measurement of the parity of on-site occupation numbers, as has
been performed in recent experiments. We illustrate these ideas for a
Superfluid-Mott insulator quench in the Bose-Hubbard model, and also for
hard-core bosons, and show that the scheme is robust against imperfections in
the measurements.Comment: 4+ pages plus supplementary materia
Quantum Spin Dimers from Chiral Dissipation in Cold-Atom Chains
We consider the non-equilibrium dynamics of a driven dissipative spin chain
with chiral coupling to a 1D bosonic bath, and its atomic implementation with a
two-species mixture of cold quantum gases. The reservoir is represented by a
spin-orbit coupled 1D quasi-condensate of atoms in a magnetized phase, while
the spins are identified with motional states of a separate species of atoms in
an optical lattice. The chirality of reservoir excitations allows the spins to
couple differently to left and right moving modes, which in our atomic setup
can be tuned from bidirectional to purely unidirectional. Remarkably, this
leads to a pure steady state in which pairs of neighboring spins form dimers
that decouple from the remainder of the chain. Our results also apply to
current experiments with two-level emitters coupled to photonic waveguides.Comment: Replaced by published version (6 pages + 8 pages supplemental
material
Raman response of Stage-1 graphite intercalation compounds revisited
We present a detailed in-situ Raman analysis of stage-1 KC8, CaC6, and LiC6
graphite intercalation compounds (GIC) to unravel their intrinsic finger print.
Four main components were found between 1200 cm-1 and 1700 cm-1, and each of
them were assigned to a corresponding vibrational mode. From a detailed line
shape analysis of the intrinsic Fano-lines of the G- and D-line response we
precisely determine the position ({\omega}ph), line width ({\Gamma}ph) and
asymmetry (q) from each component. The comparison to the theoretical calculated
line width and position of each component allow us to extract the
electron-phonon coupling constant of these compounds. A coupling constant
{\lambda}ph < 0.06 was obtained. This highlights that Raman active modes alone
are not sufficient to explain the superconductivity within the electron-phonon
coupling mechanism in CaC6 and KC8.Comment: 6 pages, 3 figures, 2 table
Cost-effectiveness analysis of the use of immunotherapy in metastatic solid tumours in Austria by applying the ESMO-magnitude of clinical benefit scale (ESMO-MCBS) version 1.1
BACKGROUND: Immune checkpoint inhibitors (ICIs) treatment is a breakthrough in managing metastatic solid tumours, but its use is associated with a high financial burden for public health care systems. Validated tools such as the European Society for Medical Oncology-Magnitude of Clinical Benefit Scale (ESMO-MCBS) are frameworks that might help to better assess the clinical benefit of these novel innovative cancer drugs. METHODS: Here, we systematically analysed the number of European Medicines Agency-approved ICIs labels with an ESMO-MCBS grade <4 and the impact of the ICIs on incremental costs, gain of life years (LYs), quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio in the Austrian population. RESULTS: Of 23 ICIs treatment settings, we identified three clinical scenarios in metastatic solid cancers with an ESMO-MCBS grade <4 with no otherwise approved alternatives. In triple-negative breast cancer (TNBC), the addition of first-line atezolizumab increased QALYs by 0.33 compared with nab-paclitaxel only, with an incremental cost per QALY of €143 853. In small-cell lung cancer (SCLC), the addition of first-line atezolizumab increased the QALY by 0.09, with an incremental cost per QALY of €373 256, and the addition of first-line durvalumab increased the QALYs by 0.11, with an incremental cost per QALY of €589 527. CONCLUSIONS: Overall, most of the approved ICIs carry significant clinical benefit (≥4). Although TNBC and SCLC are challenging treatment scenarios, currently approved ICIs with an ESMO-MCBS grade <4 substantially increase the cost of medical treatment, and under a willingness-to-pay threshold of €100 000, they do not have a cost-effective comparative benefit
Thermal vs. Entanglement Entropy: A Measurement Protocol for Fermionic Atoms with a Quantum Gas Microscope
We show how to measure the order-two Renyi entropy of many-body states of
spinful fermionic atoms in an optical lattice in equilibrium and
non-equilibrium situations. The proposed scheme relies on the possibility to
produce and couple two copies of the state under investigation, and to measure
the occupation number in a site- and spin-resolved manner, e.g. with a quantum
gas microscope. Such a protocol opens the possibility to measure entanglement
and test a number of theoretical predictions, such as area laws and their
corrections. As an illustration we discuss the interplay between thermal and
entanglement entropy for a one dimensional Fermi-Hubbard model at finite
temperature, and its possible measurement in an experiment using the present
scheme
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