5,901 research outputs found
Experimental realization of non-Abelian gauge potentials and topological Chern state in circuit system
Gauge fields, both Abelian and non-Abelian type, play an important role in
modern physics. It prompts extensive studies of exotic physics on a variety of
platforms. In this work, we present building blocks, consist of capacitors and
inductors, for implementing non-Abelian gauge fields in circuit system. Based
on these building blocks, we experimentally synthesize the Rashba-Dresselhaus
spin-orbit interaction. Using operational amplifier, to break the time reversal
symmetry, we further provide a scheme for designing the topological Chern
circuit system. By measuring the chiral edge state of the Chern circuit, we
experimentally confirm its topological nature. Our scheme offers a new route to
study physics related to non-Abelian gauge field using circuit systems
Pentaquark states with the configuration in a simple model
We discuss the mass splittings for the -wave triply heavy pentaquark
states with the configuration which is a mirror
structure of . The latter configuration is related with the nature
of observed by the LHCb Collaboration. The considered pentaquark
masses are roughly estimated with a simple method. One finds that such states
are probably not narrow even if they do exist. This leaves room for molecule
interpretation for a state around the low-lying threshold of a doubly heavy
baryon and a heavy-light meson, e.g. , if it were observed. As a by
product, we conjecture that upper limits for the masses of the conventional
triply heavy baryons can be determined by the masses of the conventional doubly
heavy baryons.Comment: 19 pages, 1 figure, 10 tables; Version accepted by Eur. Phys. J.
Absence of a transport signature of spin-orbit coupling in graphene with indium adatoms
Enhancement of the spin-orbit coupling in graphene may lead to various
topological phenomena and also find applications in spintronics. Adatom
absorption has been proposed as an effective way to achieve the goal. In
particular, great hope has been held for indium in strengthening the spin-orbit
coupling and realizing the quantum spin Hall effect. To search for evidence of
the spin-orbit coupling in graphene absorbed with indium adatoms, we carry out
extensive transport measurements, i.e., weak localization magnetoresistance,
quantum Hall effect and non-local spin Hall effect. No signature of the
spin-orbit coupling is found. Possible explanations are discussed.Comment: 5 pages, 4 figures, with supplementary material
A chalcone derivative reactivates latent HIV-1 transcription through activating P-TEFb and promoting Tat-SEC interaction on viral promoter.
The principal barrier to the eradication of HIV/AIDS is the existence of latent viral reservoirs. One strategy to overcome this barrier is to use latency-reversing agents (LRAs) to reactivate the latent proviruses, which can then be eliminated by effective anti-retroviral therapy. Although a number of LRAs have been found to reactivate latent HIV, they have not been used clinically due to high toxicity and poor efficacy. In this study, we report the identification of a chalcone analogue called Amt-87 that can significantly reactivate the transcription of latent HIV provirses and act synergistically with known LRAs such as prostratin and JQ1 to reverse latency. Amt-87 works by activating the human transcriptional elongation factor P-TEFb, a CDK9-cyclin T1 heterodimer that is part of the super elongation complex (SEC) used by the viral encoded Tat protein to activate HIV transcription. Amt-87 does so by promoting the phosphorylation of CDK9 at the T-loop, liberating P-TEFb from the inactive 7SK snRNP, and inducing the formation of the Tat-SEC complex at the viral promoter. Together, our data reveal chalcones as a promising category of compounds that should be further explored to identify effective LRAs for targeted reversal of HIV latency
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