8,323 research outputs found
Configurable unitary transformations and linear logic gates using quantum memories
We show that a set of optical memories can act as a configurable linear
optical network operating on frequency-multiplexed optical states. Our protocol
is applicable to any quantum memories that employ off-resonant Raman
transitions to store optical information in atomic spins. In addition to the
configurability, the protocol also offers favourable scaling with an increasing
number of modes where N memories can be configured to implement an arbitrary
N-mode unitary operations during storage and readout. We demonstrate the
versatility of this protocol by showing an example where cascaded memories are
used to implement a conditional CZ gate.Comment: 5 pages, 2 figure
Topology design and performance analysis of an integrated communication network
A research study on the topology design and performance analysis for the Space Station Information System (SSIS) network is conducted. It is begun with a survey of existing research efforts in network topology design. Then a new approach for topology design is presented. It uses an efficient algorithm to generate candidate network designs (consisting of subsets of the set of all network components) in increasing order of their total costs, and checks each design to see if it forms an acceptable network. This technique gives the true cost-optimal network, and is particularly useful when the network has many constraints and not too many components. The algorithm for generating subsets is described in detail, and various aspects of the overall design procedure are discussed. Two more efficient versions of this algorithm (applicable in specific situations) are also given. Next, two important aspects of network performance analysis: network reliability and message delays are discussed. A new model is introduced to study the reliability of a network with dependent failures. For message delays, a collection of formulas from existing research results is given to compute or estimate the delays of messages in a communication network without making the independence assumption. The design algorithm coded in PASCAL is included as an appendix
Optical Properties of Organometallic Perovskite: An ab initio Study using Relativistic GW Correction and Bethe-Salpeter Equation
In the development of highly efficient photovoltaic cells, solid perovskite
systems have demonstrated unprecedented promise, with the figure of merit
exceeding nineteen percent of efficiency. In this paper, we investigate the
optical and vibrational properties of organometallic cubic perovskite
CH3NH3PbI3 using first-principles calculations. For accurate theoretical
description, we go beyond conventional density functional theory (DFT), and
calculated optical conductivity using relativist quasi-particle (GW)
correction. Incorporating these many-body effects, we further solve
Bethe-Salpeter equations (BSE) for excitons, and found enhanced optical
conductivity near the gap edge. Due to the presence of organic methylammonium
cations near the center of the perovskite cell, the system is sensitive to low
energy vibrational modes. We estimate the phonon modes of CH3NH3PbI3 using
small displacement approach, and further calculate the infrared absorption (IR)
spectra. Qualitatively, our calculations of low-energy phonon frequencies are
in good agreement with our terahertz measurements. Therefore, for both energy
scales (around 2 eV and 0-20 meV), our calculations reveal the importance of
many-body effects and their contributions to the desirable optical properties
in the cubic organometallic perovskites system.Comment: 5 pages, 4 figure
Quantum study of information delay in electromagetically induced transparency
Using electromagnetically induced transparency (EIT), it is possible to delay
and store light in atomic ensembles. Theoretical modelling and recent
experiments have suggested that the EIT storage mechanism can be used as a
memory for quantum information. We present experiments that quantify the noise
performance of an EIT system for conjugate amplitude and phase quadratures. It
is shown that our EIT system adds excess noise to the delayed light that has
not hitherto been predicted by published theoretical modelling. In analogy with
other continuous-variable quantum information systems, the performance of our
EIT system is characterised in terms of conditional variance and signal
transfer.Comment: 4 pages, 4 figure
I.3 The CoRoT story
This book is dedicated to all the people interested in the CoRoT mission and the beautiful data that were delivered during its six year duration. Either amateurs, professional, young or senior researchers, they will find treasures not only at the time of this publication but also in the future twenty or thirty years. It presents the data in their final version, explains how they have been obtained, how to handle them, describes the tools necessary to understand them, and where to find them. It also highlights the most striking first results obtained up to now. CoRoT has opened several unexpected directions of research and certainly new ones still to be discovered
Renormalization of the N=1 Abelian Super-Chern-Simons Theory Coupled to Parity-Preserving Matter
We analyse the renormalizability of an Abelian N=1 super-Chern-Simons model
coupled to parity-preserving matter on the light of the regularization
independent algebraic method. The model shows to be stable under radiative
corrections and to be gauge anomaly free.Comment: Latex, 7 pages, no figure
Repurposing tofacitinib as an anti-myeloma therapeutic to reverse growth-promoting effects of the bone marrow microenvironment.
The myeloma bone marrow microenvironment promotes proliferation of malignant plasma cells and resistance to therapy. Activation of JAK/STAT signaling is thought to be a central component of these microenvironment-induced phenotypes. In a prior drug repurposing screen, we identified tofacitinib, a pan-JAK inhibitor Food and Drug Administration (FDA) approved for rheumatoid arthritis, as an agent that may reverse the tumor-stimulating effects of bone marrow mesenchymal stromal cells. Herein, we validated in vitro, in stromal-responsive human myeloma cell lines, and in vivo, in orthotopic disseminated xenograft models of myeloma, that tofacitinib showed efficacy in myeloma models. Furthermore, tofacitinib strongly synergized with venetoclax in coculture with bone marrow stromal cells but not in monoculture. Surprisingly, we found that ruxolitinib, an FDA approved agent targeting JAK1 and JAK2, did not lead to the same anti-myeloma effects. Combination with a novel irreversible JAK3-selective inhibitor also did not enhance ruxolitinib effects. Transcriptome analysis and unbiased phosphoproteomics revealed that bone marrow stromal cells stimulate a JAK/STAT-mediated proliferative program in myeloma cells, and tofacitinib reversed the large majority of these pro-growth signals. Taken together, our results suggest that tofacitinib reverses the growth-promoting effects of the tumor microenvironment. As tofacitinib is already FDA approved, these results can be rapidly translated into potential clinical benefits for myeloma patients
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