Cosmic rays’ interactions with the residual atmosphere surrounding the Earth produce a variety of particles, like electrons, positrons, protons, anti-protons, and Helium nuclei that can be observed ...below the local geomagnetic cutoff. In this work, we present new measurements of downward-going, albedo proton fluxes with kinetic energy in the range ∼40–∼250 MeV, performed by the High-Energy Particle Detector (HEPD-01) on board of the China Seismo-Electromagnetic Satellite - CSES-01 - at an altitude of ∼500 km. Employing a dedicated trajectory-tracing simulation routine, the protons collected by HEPD-01 are classified into quasi-trapped (QT), long lifetime (≳10 s) particles concentrating in the equatorial region of the Earth, and un-trapped (UT), distributed at all latitudes; the latter includes both precipitating short lifetime particles (UTS) and pseudo-trapped long lifetime (UTL) populations, abundant in the so-called penumbra regions. The temporal trend of re-entrant protons between 2018 and 2022 is also reported, assessing the stability of such population during the data-taking period of HEPD-01; this highlights their independence from the long-term modulating effect of the solar activity.
•A study of re-entrant albedo protons in the Earth’s magnetosphere as a function of energy with the HEPD-01 payload is presented.•A comparison with past experiments is carried out, with good results.•Time-profiles of re-entrant albedo protons show a general stability during the analyzed period.
We consider the generators of gauge transformations with test functions which do not vanish on the boundary of a spacelike region of interest. These are known to generate the edge degrees of freedom ...in a gauge theory. In this paper, we augment these by introducing the dual or magnetic analogue of such operators. We then study the algebra of these operators, focusing on implications for the superselection sectors of the gauge theory. A manifestly duality-invariant action is also considered, from which alternate descriptions which are \(SL(2, \mathbb{Z})\) transforms of each other can be obtained. We also comment on a number of issues related to local charges, definition of confinement and the appearance of interesting mathematical structures such as the Drinfel'd double and the Manin triple.
The observables associated with a quantum system \(S\) form a non-commutative algebra \({\mathcal A}_S\). It is assumed that a density matrix \(\rho\) can be determined from the expectation values of ...observables. But \(\mathcal A_S\) admits inner automorphisms \(a\mapsto uau^{-1},\; a,u\in {\mathcal A}_S\), \(u^*u=u^*u=1\), so that its individual elements can be identified only up to unitary transformations. So since \(\mathrm{Tr} \rho (uau^*)= \mathrm{Tr} (u^*\rho u)a\), only the spectrum of \(\rho\), or its characteristic polynomial, can be determined in quantum mechanics. In local quantum field theory, \(\rho\) cannot be determined at all, as we shall explain. However, abelian algebras do not have inner automorphisms, so the measurement apparatus can determine mean values of observables in abelian algebras \({\mathcal A}_M\subset {\mathcal A}_S\) (\(M\) for measurement, \(S\) for system). We study the uncertainties in extending \(\rho|_{{\mathcal A}_M}\) to \(\rho|_{{\mathcal A}_S}\) (the determination of which means measurement of \({\mathcal A}_S\)) and devise a protocol to determine \(\rho|_{{\mathcal A}_S}\equiv \rho\) by determining \(\rho|_{{\mathcal A}_M}\) for different choices of \({\mathcal A}_M\). The problem we formulate and study is a generalization of the Kadison-Singer theorem. We give an example where the system \(S\) is a particle on a circle and the experiment measures the abelian algebra of a magnetic field \(B\) coupled to \(S\). The measurement of \(B\) gives information about the state \(\rho\) of the system \(S\) due to operator mixing. Associated uncertainty principles for von Neumann entropy are discussed in the appendix, adapting the earlier work of Białynicki-Birula and Mycielski to the present case.
Since echinocandins are recommended as first line therapy for invasive candidiasis, detection of resistance, mainly due to alteration in FKS protein, is of main interest. EUCAST AFST recommends ...testing both MIC of anidulafungin and micafungin, and breakpoints (BPs) have been proposed to detect echinocandin-resistant isolates. We analyzed MIC distribution for all three available echinocandins of 2,787 clinical yeast isolates corresponding to 5 common and 16 rare yeast species, using the standardized EUCAST method for anidulafungin and modified for caspofungin and micafungin (AM3-MIC). In our database, 64 isolates of common pathogenic species were resistant to anidulafungin, according to the EUCAST BP, and/or to caspofungin, using our previously published threshold (AM3-MIC ≥ 0.5 mg/L). Among these 64 isolates, 50 exhibited 21 different FKS mutations. We analyzed the capacity of caspofungin AM3-MIC and anidulafungin MIC determination in detecting isolates with FKS mutation. They were always identified using caspofungin AM3-MIC and the local threshold while some isolates were misclassified using anidulafungin MIC and EUCAST threshold. However, both methods misclassified four wild-type C. glabrata as resistant. Based on a large data set from a single center, the use of AM3-MIC testing for caspofungin looks promising in identifying non-wild-type C. albicans, C. tropicalis and P. kudiravzevii isolates, but additional multicenter comparison is mandatory to conclude on the possible superiority of AM3-MIC testing compared to the EUCAST method.
Motivated by the sharp contrast between classical and quantum physics as probability theories, in these lecture notes I introduce the basic notions of operator algebras that are relevant for the ...algebraic approach to quantum physics. Aspects of the representation theory of C*-algebras will be motivated and illustrated in physical terms. Particular emphasis will be given to explicit examples from the theory of quantum phase transitions, where concepts coming from strands as diverse as quantum information theory, algebraic quantum physics and statistical mechanics agreeably converge, providing a more complete picture of the physical phenomena involved.
Ground states of quadratic Hamiltonians for fermionic systems can be characterized in terms of orthogonal complex structures. The standard way in which such Hamiltonians are diagonalized makes use of ...a certain "doubling" of the Hilbert space. In this work we show that this redundancy in the Hilbert space can be completely lifted if the relevant orthogonal structure is taken into account. Such an approach allows for a treatment of Majorana fermions which is both physically and mathematically transparent. Furthermore, an explicit connection between orthogonal complex structures and the topological \(\mathbb Z_2\)-invariant is given.
The algebraic approach to quantum physics emphasizes the role played by the structure of the algebra of observables and its relation to the space of states. An important feature of this point of view ...is that subsystems can be described by subalgebras, with partial trace being replaced by the more general notion of restriction to a subalgebra. This, in turn, has recently led to applications to the study of entanglement in systems of identical particles. In the course of those investigations on entanglement and particle identity, an emergent gauge symmetry has been found by Balachandran, de Queiroz and Vaidya. In this letter we establish a novel connection between that gauge symmetry, entropy production and quantum operations. Thus, let A be a system described by a finite dimensional observable algebra and \(\omega\) a mixed faithful state. Using the Gelfand-Naimark-Segal (GNS) representation we construct a canonical purification of \(\omega\), allowing us to embed A into a larger system C. Using Tomita-Takasaki theory, we obtain a subsystem decomposition of C into subsystems A and B, without making use of any tensor product structure. We identify a group of transformations that acts as a gauge group on A while at the same time giving rise to entropy increasing quantum operations on C. We provide physical means to simulate this gauge symmetry/quantum operation duality.
•Four triethylammonium salts essential for pharmacology were investigated.•The crystal structure, chemical environment, and interactions were studied.•The proton tautomerism and stereoisomerism were ...studied.•The effect of counter ions on the hydrogen bond network was analyzed.•The resonance effect spreading from the enoxide to the SO2 group is observed.
The investigated symmetrical bis-adducts, i.e., bis(1-ethyl-4‑hydroxy-2,2-dioxido-1H-2,1-benzothiazin-3-yl)(furan-2-yl/phenyl)methane and bis(4‑hydroxy-2,2-dioxido-2H-1,2-benzoxathiin-3-yl)(furan-2-yl/4-methoxyphenyl)methane, essential objects for pharmacological studies, were found to exist in the liquid and solid phases in a double tautomeric enol form which allows the existence of acid-base interactions related to the proton transfer to the triethylamine and the formation of an intramolecular O―H···O− hydrogen bond between the intact OH group and the enolate O− atom. In the crystal lattice of triethylammonium salts containing 1,2-benzoxathiine 2,2-dioxide moieties in the anion molecules, counter ions are connected by N―H···O hydrogen bonds, in which the enolate O− atom plays the role of a proton acceptor. Whereas in crystals with 2,1-benzothiazine 2,2-dioxide fragments in the anion molecules cation and anion molecules are linked by N—H···O hydrogen bonds, in which the role of a proton acceptor is played by an O atom of a sulphonyl group that belongs to a bicyclic fragment which contains an enolate group. We have shown that the dipole-dipole interactions in the investigated ammonium salts may explain the orientation of the cationic N−H group once to the O− atom of the enolate group, another time to the O atom of the sulfonyl group. The effect of the structure of the anion molecule on the hydrogen bonding network in the crystals studied was analyzed by the X-ray diffraction method, the 1H and 13C NMR technique including COSY, NOESY, HSQC and HMBC two-dimensional patterns, and the Fourier transform infrared (FTIR) spectroscopy. Theoretical analysis of the interactions in the crystals was performed using Density Functional Theory (DFT) and Quantum Theory of Atoms in Molecules (QTAIM).
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