767 research outputs found
Discovery reach for wino and higgsino dark matter with a disappearing track signature at a 100 TeV collider
Within the theory of supersymmetry, the lightest neutralino is a dark matter
candidate and is often assumed to be the lightest supersymmetric particle (LSP)
as well. If the neutral wino or higgsino is dark matter, the upper limit of the
LSP mass is determined by the observed relic density of dark matter. If the LSP
is a nearly-pure neutral state of the wino or higgsino, the lightest chargino
state is expected to have a significant lifetime due to a tiny mass difference
between the LSP and the chargino. This article presents discovery potential of
the 100 TeV future circular hadron collider (FCC) for the wino and higgsino
dark matter using a disappearing-track signature. The search strategy to extend
the discovery reach to the thermal limits of wino/higgsino dark matter is
discussed with detailed studies on the background rate and the reference design
of the FCC-hadron detector under possible running scenarios of the FCC-hadron
machine. A proposal of modifying the detector layout and several ideas to
improve the sensitivity further are also discussed.Comment: 10 pages, 7 figures, 4 table
Resolution enhancement of one-dimensional molecular wavefunctions in plane-wave basis via quantum machine learning
Super-resolution is a machine-learning technique in image processing which
generates high-resolution images from low-resolution images. Inspired by this
approach, we perform a numerical experiment of quantum machine learning, which
takes low-resolution (low plane-wave energy cutoff) one-particle molecular
wavefunctions in plane-wave basis as input and generates high-resolution (high
plane-wave energy cutoff) wavefunctions in fictitious one-dimensional systems,
and study the performance of different learning models. We show that the
trained models can generate wavefunctions having higher fidelity values with
respect to the ground-truth wavefunctions than a simple linear interpolation,
and the results can be improved both qualitatively and quantitatively by
including data-dependent information in the ansatz. On the other hand, the
accuracy of the current approach deteriorates for wavefunctions calculated in
electronic configurations not included in the training dataset. We also discuss
the generalization of this approach to many-body electron wavefunctions.Comment: 13 pages, 18 figure
Steady shocks around black holes produced by sub-keplerian flows with negative energy
We discuss a special case of formation of axisymmetric shocks in the
accretion flow of ideal gas onto a Schwarzschild black hole: when the total
energy of the flow is negative. The result of our analysis enlarges the
parameter space for which these steady shocks are exhibited in the accretion of
gas rotating around relativistic stellar objects. Since keplerian disks have
negative total energy, we guess that, in this energy range, the production of
the shock phenomenon might be easier than in the case of positive energy. So
our outcome reinforces the view that sub-keplerian flows of matter may
significantly affect the physics of the high energy radiation emission from
black hole candidates. We give a simple procedure to obtain analytically the
position of the shocks. The comparison of the analytical results with the data
of 1D and 2D axisymmetric numerical simulations confirms that the shocks form
and are stable.Comment: 5 pages, 5 figures, accepted by MNRAS on 10 November 200
Quantum Gate Pattern Recognition and Circuit Optimization for Scientific Applications
There is no unique way to encode a quantum algorithm into a quantum circuit.
With limited qubit counts, connectivities, and coherence times, circuit
optimization is essential to make the best use of near-term quantum devices. We
introduce two separate ideas for circuit optimization and combine them in a
multi-tiered quantum circuit optimization protocol called AQCEL. The first
ingredient is a technique to recognize repeated patterns of quantum gates,
opening up the possibility of future hardware co-optimization. The second
ingredient is an approach to reduce circuit complexity by identifying zero- or
low-amplitude computational basis states and redundant gates. As a
demonstration, AQCEL is deployed on an iterative and efficient quantum
algorithm designed to model final state radiation in high energy physics. For
this algorithm, our optimization scheme brings a significant reduction in the
gate count without losing any accuracy compared to the original circuit.
Additionally, we have investigated whether this can be demonstrated on a
quantum computer using polynomial resources. Our technique is generic and can
be useful for a wide variety of quantum algorithms.Comment: 22 pages, 16 figure
Increased Expression of Proliferating Cell Nuclear Antigen in Rejecting Rat Lung Allografts
The aim of this study was to investigate the expression of proliferating cell nuclear antigen (PCNA) as an index of cell proliferation in the Brown Norway (BN) to Lewis (LEW) rat lung allograft model.Following transplantation of BN left lungs into LEW recipients, counts of PCNA-positive cells in the perivascular cellular infiltrate and bronchus-associated lymphoid tissue (BALT) were compared with the histological grade of rejection. Lungs were excised on postoperative days 3 and 5. LEW-to-LEW donor-recipient transplantation was performed as a control. Routinely processed, paraffinembedded sections were selected and stained with PCNA. The PCNA index (% of nuclei positive for PCNA) in the BALT was significantly higher in allograft (19.1%, p < 0.05) compared with isograft (4.2%) at 3 days following transplantation. Similarly, the PCNA index was also greater in the perivascular cellular infiltrates of rejecting lungs (23.9% at 3 days, 31.6% at 5 days). These findings indicate that the cells stimulated by the rejection reaction could be increase the expression of PCNA, and the increasing severity of rejection was paralleled by an increase in the number of PCNA-positive cells. In conclusion, PCNA may be a useful marker of acute cellular rejection in lung allografts
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