16,032 research outputs found
The Hawking-Page phase transitions in the extended phase space in the Gauss-Bonnet gravity
In this paper, the Hawking-Page phase transitions between the black holes and
thermal anti-de Sitter (AdS) space are studied with the Gauss-Bonnet term in
the extended phase space, in which the varying cosmological constant plays the
role of an effective thermodynamic pressure. The Gauss-Bonnet term exhibits its
effects via introducing the corrections to the black hole entropy and Gibbs
free energy. The global phase structures, especially the phase transition
temperature and the Gibbs free energy , are systematically
investigated, first for the Schwarzschild-AdS black holes and then for the
charged and rotating AdS black holes in the grand canonical ensembles, with
both analytical and numerical methods. It is found that there are terminal
points in the coexistence lines, and decreases at large electric
potentials and angular velocities and also decreases with the Gauss-Bonnet
coupling constant .Comment: 13 pages, 13 figure
A Submillimeter Burst of S255IR~SMA1 - The Rise And Fall Of Its Luminosity
Temporal photometric variations at near infrared to submillimeter wavelengths
have been found in low-mass young stellar objects. These phenomena are
generally interpreted as accretion events of star-disk systems with varying
accretion rates. There is growing evidence suggesting that similar luminosity
flaring also occurs in high-mass star/cluster-forming regions. We report in
this Letter the rise and fall of the 900 m continuum emission and the
newly found 349.1 GHz methanol maser emission in the massive star forming
region S255IR~SMA1 observed with the Submillimeter Array and the Atacama Large
Millimeter/submillimeter Array. The level of flux variation at a factor of
2 at the submillimeter band and the relatively short 2-year duration of
this burst suggest that the event is probably similar to those milder and more
frequent minor bursts seen in 3D numerical simulations.Comment: 8 pages, 4 figures, Accepted for publication in The Astrophysical
Journal Lette
Endocidal Regulation of Secondary Metabolites in the Producing Organisms
Secondary metabolites are defined as organic compounds that are not directly involved in the normal growth, development, and reproduction of an organism. They are widely believed to be responsible for interactions between the producing organism and its environment, with the producer avoiding their toxicities. In our experiments, however, none of the randomly selected 44 species representing different groups of plants and insects can avoid autotoxicity by its endogenous metabolites once made available. We coined the term endocides (endogenous biocides) to describe such metabolites that can poison or inhibit the parent via induced biosynthesis or external applications. Dosage-dependent endocides can selectively induce morphological mutations in the parent organism (e.g., shrubbiness/dwarfism, pleiocotyly, abnormal leaf morphogenesis, disturbed phyllotaxis, fasciated stems, and variegation in plants), inhibit its growth, development, and reproduction and cause death than non-closely related species. The propagule, as well as the organism itself contains or produces adequate endocides to kill itself
Biscarbamate cross-linked polyethylenimine derivative with low molecular weight, low cytotoxicity, and high efficiency for gene delivery
Polyethylenimine (PEI), especially PEI 25 kDa, has been widely studied for delivery of nucleic acid drugs both in vitro and in vivo. However, it lacks degradable linkages and is too toxic for therapeutic applications. Hence, low-molecular-weight PEI has been explored as an alternative to PEI 25 kDa. To reduce cytotoxicity and increase transfection efficiency, we designed and synthesized a novel small-molecular-weight PEI derivative (PEI-Et, Mn: 1220, Mw: 2895) with ethylene biscarbamate linkages. PEI-Et carried the ability to condense plasmid DNA (pDNA) into nanoparticles. Gel retardation assay showed complete condensation of pDNA at w/w ratios that exceeded three. The particle size of polymer/pDNA complexes was between 130 nm and 180 nm and zeta potential was 5–10 mV, which were appropriate for cell endocytosis. The morphology of PEI-Et/pDNA complexes observed by atomic force microscopy (AFM) was spherically shaped with diameters of 110–190 nm. The transfection efficiency of polymer/pDNA complexes as determined with the luciferase activity assay as well as fluorescence-activated cell-sorting analysis (FACS) was higher than commercially available PEI 25 kDa and Lipofectamine 2000 in various cell lines. Also, the polymer exhibited significantly lower cytotoxicity compared to PEI 25 kDa at the same concentration in three cell lines. Therefore, our results indicated that the PEI-Et would be a promising candidate for safe and efficient gene delivery in gene therapy
Quantifying the magic of quantum channels
To achieve universal quantum computation via general fault-tolerant schemes,
stabilizer operations must be supplemented with other non-stabilizer quantum
resources. Motivated by this necessity, we develop a resource theory for magic
quantum channels to characterize and quantify the quantum "magic" or
non-stabilizerness of noisy quantum circuits. For qudit quantum computing with
odd dimension , it is known that quantum states with non-negative Wigner
function can be efficiently simulated classically. First, inspired by this
observation, we introduce a resource theory based on completely
positive-Wigner-preserving quantum operations as free operations, and we show
that they can be efficiently simulated via a classical algorithm. Second, we
introduce two efficiently computable magic measures for quantum channels,
called the mana and thauma of a quantum channel. As applications, we show that
these measures not only provide fundamental limits on the distillable magic of
quantum channels, but they also lead to lower bounds for the task of
synthesizing non-Clifford gates. Third, we propose a classical algorithm for
simulating noisy quantum circuits, whose sample complexity can be quantified by
the mana of a quantum channel. We further show that this algorithm can
outperform another approach for simulating noisy quantum circuits, based on
channel robustness. Finally, we explore the threshold of non-stabilizerness for
basic quantum circuits under depolarizing noise.Comment: 44 pages, 7 figures; v2 close to published versio
Efficiently Computable Bounds for Magic State Distillation
Magic-state distillation (or nonstabilizer state manipulation) is a crucial component in the leading approaches to realizing scalable, fault-tolerant, and universal quantum computation. Related to nonstabilizer state manipulation is the resource theory of nonstabilizer states, for which one of the goals is to characterize and quantify nonstabilizerness of a quantum state. In this Letter, we introduce the family of thauma measures to quantify the amount of nonstabilizerness in a quantum state, and we exploit this family of measures to address several open questions in the resource theory of nonstabilizer states. As a first application, we establish the hypothesis testing thauma as an efficiently computable benchmark for the one-shot distillable nonstabilizerness, which in turn leads to a variety of bounds on the rate at which nonstabilizerness can be distilled, as well as on the overhead of magic-state distillation. We then prove that the max-thauma can be used as an efficiently computable tool in benchmarking the efficiency of magic-state distillation, and that it can outperform previous approaches based on mana. Finally, we use the min-thauma to bound a quantity known in the literature as the regularized relative entropy of magic. As a consequence of this bound, we find that two classes of states with maximal mana, a previously established nonstabilizerness measure, cannot be interconverted in the asymptotic regime at a rate equal to one. This result resolves a basic question in the resource theory of nonstabilizer states and reveals a difference between the resource theory of nonstabilizer states and other resource theories such as entanglement and coherence
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