On the spectrum of closed k=2 flux tubes in D=2+1 SU(N) gauge theories

We calculate the energy spectrum of a k=2 flux tube that is closed around a spatial torus, as a function of its length l. We do so for SU(4) and SU(5) gauge theories in 2 space dimensions. We find that to a very good approximation the eigenstates belong to the irreducible representations of the SU(N) group rather than just to its center, Z_N. We obtain convincing evidence that the low-lying states are, for l not too small, very close to those of the Nambu-Goto free string theory (in flat space-time). The correction terms appear to be typically of O(1) in appropriate units, much as one would expect if the bosonic string model were an effective string theory for the dynamics of these flux tubes. This is in marked contrast to the case of fundamental flux tubes where such corrections have been found to be unnaturally small. Moreover we find that these corrections appear to be particularly small when the `phonons' along the string have the same momentum, and large when their momentum is opposite. This provides information about the detailed nature of the interactions in the effective string theory. We have searched for, but not found, extra states that would arise from the excitation of the massive modes presumably associated with the non-trivial structure of the flux tube.Comment: 37 pages, 16 figures, minor changes to text and figure

Nonclassical correlations of phase noise and photon number in quantum nondemolition measurements

The continuous transition from a low resolution quantum nondemolition measurement of light field intensity to a precise measurement of photon number is described using a generalized measurement postulate. In the intermediate regime, quantization appears as a weak modulation of measurement probability. In this regime, the measurement result is strongly correlated with the amount of phase decoherence introduced by the measurement interaction. In particular, the accidental observation of half integer photon numbers preserves phase coherence in the light field, while the accidental observation of quantized values increases decoherence. The quantum mechanical nature of this correlation is discussed and the implications for the general interpretation of quantization are considered.Comment: 16 pages, 5 figures, final version to be published in Phys. Rev. A, Clarifications of the nature of the measurement result and the noise added in section I

Hilbert Lattice Equations

There are five known classes of lattice equations that hold in every infinite dimensional Hilbert space underlying quantum systems: generalised orthoarguesian, Mayet's E_A, Godowski, Mayet-Godowski, and Mayet's E equations. We obtain a result which opens a possibility that the first two classes coincide. We devise new algorithms to generate Mayet-Godowski equations that allow us to prove that the fourth class properly includes the third. An open problem related to the last class is answered. Finally, we show some new results on the Godowski lattices characterising the third class of equations.Comment: 24 pages, 3 figure

Boson-fermion unification, superstrings, and Bohmian mechanics

Bosonic and fermionic particle currents can be introduced in a more unified way, with the cost of introducing a preferred spacetime foliation. Such a unified treatment of bosons and fermions naturally emerges from an analogous superstring current, showing that the preferred spacetime foliation appears only at the level of effective field theory, not at the fundamental superstring level. The existence of the preferred spacetime foliation allows an objective definition of particles associated with quantum field theory in curved spacetime. Such an objective definition of particles makes the Bohmian interpretation of particle quantum mechanics more appealing. The superstring current allows a consistent Bohmian interpretation of superstrings themselves, including a Bohmian description of string creation and destruction in terms of string splitting. The Bohmian equations of motion and the corresponding probabilistic predictions are fully relativistic covariant and do not depend on the preferred foliation.Comment: 30 pages, 1 figure, revised, to appear in Found. Phy

EPR-Bell Nonlocality, Lorentz Invariance, and Bohmian Quantum Theory

We discuss the problem of finding a Lorentz invariant extension of Bohmian mechanics. Due to the nonlocality of the theory there is (for systems of more than one particle) no obvious way to achieve such an extension. We present a model invariant under a certain limit of Lorentz transformations, a limit retaining the characteristic feature of relativity, the non-existence of absolute time resp. simultaneity. The analysis of this model exemplifies an important property of any Bohmian quantum theory: the quantum equilibrium distribution $\rho = |\psi |^2$ cannot simultaneously be realized in all Lorentz frames of reference.Comment: 24 pages, LaTex, 4 figure

Dioctahedral mixed K-Na-micas and paragonite in diagenetic to low-temperature metamorphic terrains: bulk rock chemical, thermodynamic and textural constraints

Abstract Metamorphic mineral assemblages in low-temperature metaclastic rocks often contain paragonite and/or its precursor metastable phase (mixed K-Na-white mica). Relationships between the bulk rock major element chemistries and the formation of paragonite at seven localities from Central and SE-Europe were studied, comparing the bulk chemical characteristics with mineral assemblage, mineral chemical and metamorphic petrological data. Considerable overlaps between the projection fields of bulk chemistries of the Pg-free and Pg-bearing metaclastic rocks indicate significant differences between the actual (as analyzed) and effective bulk chemical compositions. Where inherited, clastic, inert phases/constituents were excluded, it was found that a decrease in Na/(Na+Al*) and in K/(K+Al*) ratios of rocks favors the formation and occurrence of Pg and its precursor phases (Al* denotes here the atomic quantity of aluminum in feldspars, white micas and “pure” hydrous or anhydrous aluminosilicates). In contrast to earlier suggestions, enrichment in Na and/or an increase in Na/K ratio by themselves do not lead to formation of paragonite. Bulk rock chemistries favorable to formation of paragonite and its precursor phases are characterized by enrichment in Al and depletion in Na, K, Ca (and also, Mg and Fe2+). Such bulk rock chemistries are characteristic of chemically “mature” (strongly weathered) source rocks of the pelites and may also be formed by synand post-sedimentary magmatism-related hydrothermal (leaching) activity. What part of the whole rock is active in determining the effective bulk chemistry was investigated by textural examination of diagenetic and anchizone-grade samples. It is hypothesized that although solid phases act as local sources and sinks, transport of elements such as Na through the grain boundaries have much larger communication distances. Sodium-rich white micas nucleate heterogeneously using existing phyllosilicates as templates and are distributed widely on the thin section scale. The results of modeling by THERMOCALC suggest that paragonite preferably forms at higher pressures in low-T metapelites. The stability fields of Pg-bearing assemblages increase, the Pg-in reaction line is shifted towards lower pressures, while the stability field of the Chl-Ms-Ab-Qtz assemblage decreases and is shifted towards higher temperatures with increasing Al* content and decreasing Na/(Na+Al*) and K/(K+Al*) ratios

Interferometry with independent Bose-Einstein ondensates: parity as an EPR/Bell quantum variable

When independent Bose-Einstein condensates (BEC), described quantum mechanically by Fock (number) states, are sent into interferometers, the measurement of the output port at which the particles are detected provides a binary measurement, with two possible results $\pm1$. With two interferometers and two BEC's, the parity (product of all results obtained at each interferometer) has all the features of an Einstein-Podolsky-Rosen quantity, with perfect correlations predicted by quantum mechanics when the settings (phase shifts of the interferometers) are the same. When they are different, significant violations of Bell inequalities are obtained. These violations do not tend to zero when the number $N$ of particles increases, and can therefore be obtained with arbitrarily large systems, but a condition is that all particles should be detected. We discuss the general experimental requirements for observing such effects, the necessary detection of all particles in correlation, the role of the pixels of the CCD detectors, and that of the alignments of the interferometers in terms of matching of the wave fronts of the sources in the detection regions. Another scheme involving three interferometers and three BEC's is discussed; it leads to Greenberger Horne Zeilinger (GHZ) sign contradictions, as in the usual GHZ case with three particles, but for an arbitrarily large number of them. Finally, generalizations of the Hardy impossibilities to an arbitrarily large number of particles are introduced. BEC's provide a large versality for observing violations of local realism in a variety of experimental arrangements.Comment: appendix adde

Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society