Ghost Number Research Articles

Anomalies in covariant fracton theories

Covariant (Lorentz invariant) fracton matter, minimally coupled and charged under a symmetric rank two gauge tensor, is considered. The gauge transformations correspond to linearized longitudinal diffeomorphisms. Consistent possible anomalies are computed using the cohomology method. They depend only on the gauge field, treated as a background field, and on the gauge parameter, promoted to an anticommuting scalar ghost field. The problem is phrased in terms of polyforms, whose total degree is the sum of the form degree and of the ghost number. The most general anomaly in two dimensions and in four dimensions is computed, and an anomaly in arbitrary dimensions is individuated. In conclusion, it is shown that a simple higher-derivative scalar field theory is an example of covariant fracton matter. Published by the American Physical Society 2024

Closed string vertex operators with various ghost number

We construct closed string vertex operators with various ghost numbers in addition to the conventional ones, using the Faddeev-Popov procedure for the gauge fixing of the conformal Killing group, from matter primary fields. We find that these operators give solutions to the descent equations in the framework of the BRST formalism. Similarly, we also construct solutions to the descent equations for the dilaton vertex operator with the Lorentz covariant form. Using the unintegrated vertex operator of the dilaton with the ghost number three, we obtain the correct result of the tadpole amplitude on the disk, including a non-zero contribution from a BRST exact term which comes from a conformal transformation.

Two-point closed string amplitudes in the BRST formalism

Two-point tree-level amplitudes in bosonic closed string theory are described by a correlation function within the BRST formalism, which respects manifest Lorentz and conformal invariance. In the derivation of the two-point amplitudes, we use the mostly BRST exact operator, which has been introduced for two-point open string amplitudes, and a closed string vertex with ghost number three, which has been explored in our recent work, in addition to the conventional one.

On the spectrum around numerical solutions in Siegel gauge in open string field theory

Abstract In bosonic open string field theory, the spectrum around the numerical tachyon vacuum solution in Siegel gauge was investigated by Giusto and Imbimbo. Using their numerical method, we study the mass spectrum around two other solutions, which are “double brane” and “single brane” solutions in Siegel gauge constructed by the level truncation approximation. The “double brane” solution was constructed by Kudrna and Schnabl and its energy might correspond to a double brane. On the other hand, the “single brane” solution was constructed by Takahashi and the author in the theory around the identity-based solution for the tachyon vacuum and its energy corresponds to the perturbative vacuum, namely, a single brane. From the eigenvalues of the matrix for the kinetic term in Siegel gauge, we find a tachyon state and a massless vector state in the ghost number g = 1 sector around the “single brane” solution, which is consistent with the perturbative vacuum, although the mass spectrum around the “double brane” solution is obscure up to truncation level L = 10 and within scalar and vector states.

Efficient tile-based rendering of lens flare ghosts

The lens flare phenomenon is often an undesired artifact of the imaging process; however, it has become an important artistic tool in photography and cinematography as well as a highly impactful component for increasing the level of realism for computer-generated images. In this paper, we present a novel method for efficiently simulating the lens flares of optical camera systems in highly interactive environments. Recreating this effect in a physically correct way necessitates the use of ray tracing, which we made much more computationally efficient by using a tiled approach to rasterize the ghosts of the lens flare. One of the main drawbacks of the current state-of-the-art method is the huge pixel overdraw resulting from the large number of ghosts being rasterized individually onto the output image. The problem is made even worse when dense ray grids are utilized for improving the quality of the simulation. We overcome these limitations by collecting all the ray-traced ghost data into screen-aligned tiles and accumulating the per-pixel contributions in a single pass. We demonstrate that our tiled approach significantly outperforms the previous algorithm, scales much better with the number of flares rendered, and facilitates the efficient simulation of lens flares in real-time applications, while maintaining the physical correctness.

A Minimal b Ghost

AbstractThe b ghost, or b operator, used for fixing Siegel gauge in the pure spinor superfield formalism, is a composite operator of negative ghost number, satisfying , where q is the pure spinor differential (BRST operator). It is traditionally constructed using non‐minimal variables. However, since all cohomology has minimal representatives, it seems likely that there should be versions of physically meaningful operators, also with negative ghost number, using only minimal variables. The purpose of this letter is to demonstrate that this statement holds by providing a concrete construction in super‐Yang–Mills theory, and to argue that it is a general feature in the pure spinor superfield formalism.

Taming the 11D pure spinor b-ghost

We provide an alternative compact expression for the 11D pure spinor b-ghost by introducing a new set of negative ghost number operators made out of non-minimal pure spinor variables. Using the algebraic properties satisfied by these operators, it will be straightforwardly shown that left{Q,bright}=frac{P^2}{2} , as well as {b, b} = QΩ. As an application of this novel formulation, the ghost number two vertex operator will easily be obtained in a completely covariant manner from a standard descent relation, the ghost number three vertex operator will be shown to satisfy the generalized Siegel gauge condition, and the 11D supergravity two-particle superfield will be constructed in a quite simple way.

Comparison of human PEX knockout cell lines suggests a dual role of PEX1 in peroxisome biogenesis.

For the biogenesis and maintenance of peroxisomes several proteins, called peroxins, are essential. Malfunctions of these proteins lead to severe diseases summarized as peroxisome biogenesis disorders. The different genetic background of patient-derived cell lines and the residual expression of mutated PEX genes impede analysis ofthe whole spectrum of cellular functions of affected peroxins. To overcome these difficulties, we have generated a selected PEX knockout resource of HEK T-REx293 cells using the CRISPR/Cas9 technique. Comparative analyses of whole cell lysates revealed PEX-KO specific alterations in the steady-state level of peroxins and variations in the import efficacy of matrix proteins with a Type 2 peroxisomal targeting signal. One of the observed differences concerned PEX1 as in the complete absence of the protein, the number of peroxisomal ghosts is significantly increased. Upon expression of PEX1, import competence and abundance of peroxisomes was adjusted to the level of normal HEK cells. In contrast, expression of an alternatively spliced PEX1 isoform lacking 321 amino acids of the N-terminal region failed to rescue the peroxisomal import defects but reduced the number of peroxisomal vesicles. All in all, the data suggest a novel 'moonlighting' function of human PEX1 in the regulation of pre-peroxisomal vesicles.

Cellular composition of the black scorpionfish (Scorpaena porcus, L 1758) blood and head kidney under short-time acute exposure to hypoxia.

In the present work, we studied the effect of short-term acute hypoxia on the cellular composition of the blood and the head kidney of the black scorpionfish. Dissolved oxygen concentration was decreased from 8.5-8.7mg O2 l-1 (normoxia) to 3-5mg O2 l-1 (relative normoxia), 1-3mg O2 l-1 (moderate hypoxia), and 0-1mg O2 l-1 (acute hypoxia) within 1.5-2h by bubbling of water with N2. Exposure period was 4h, water temperature was adjusted to 14-16°C, and photoperiod was 12h (light). Short-time acute hypoxia induced a rapid release of blast and immature cells from the head kidney into the circulating blood of the black scorpionfish, which was associated with reduction in erythropoietic reserves in 2.5 times. The number of immature erythroid cells (pronormoblasts, basophilic and polychromatophilic normoblasts) significantly increased in blood, and the simultaneously relative decrease of the number of abnormal red blood cell (RBC) and the increase of the number of RBC ghosts (lysed RBCs) in circulating blood were observed. The significant correlation between methemoglobin concentration and the number of RBC ghosts was shown (R2 = 0.640 or r = 0.800). Hypoxia induced RBC swelling on 5-6% compared to control. The number of RBC ghosts in the blood is likely involved in the stimulation of erythropoietin production under hypoxia.

Quantum states and their back-reacted geometries in 2D dilaton gravity

Within the Russo-Susskind-Thorlacius (RST) two-dimensional model that includes a scalar (dilaton) field we address the important question of how the classical black hole geometry is modified in a semiclassical gravitational theory. It is the principle goal of this paper to analyze what is the back-reacted geometry that corresponds to a given quantum state. The story is shown to be dramatically different for the Hartle-Hawking state (HH) and for the Boulware state. In the HH case the back-reacted geometry is a modification of the classical black hole metric that still has a smooth horizon with a regular curvature. On the other hand, for the Boulware state the classical horizon is replaced by a throat in which the $(tt)$ component of the metric (while nonzero) is extremely small. The value of the metric at the throat is bounded by the inverse of the classical black hole entropy. On the other side of the throat the spacetime is ended at a null singularity. More generally, we identify a family of quantum states and their respective back-reacted geometries. We also identify a certain duality in the space of states. Finally, we study a hybrid setup where both physical and nonphysical fields, such as the ghosts, could be present. We suggest that it is natural to associate ghosts with the Boulware state, while the physical fields can be in any quantum state. In particular, if the physical fields are in the HH state, then the corresponding semiclassical geometry is horizonless. Depending on the balance between the number of physical fields and ghosts, it generically has a throat that may join with another asymptotically flat region on the other side of the throat.

Deformations of supergravity and supersymmetry anomalies

We present a BRST analysis of supersymmetry anomalies of mathcal{N} = 1 supersymmetric quantum field theories with anomalous R symmetry. To this end, we consider the coupling of the matter theory to classical mathcal{N} = 1 new minimal supergravity. We point out that a supersymmetry anomaly cocycle associated to the U(1)R field does exist for this theory. It is non-trivial in the space of supergravity fields (and ghosts), but it becomes BRST-exact in the functional space that includes antifields. Equivalently, the U(1)R supersymmetry anomaly cocycle vanishes “on-shell”. It is therefore removable. However, to remove it — precisely because it is not trivial in the smaller space of fields — one needs to deform the supergravity BRST operator. This deformation is triggered, at first order in the anomaly coefficient, by a local operator S1 of ghost number 1. We give a cohomological characterization of S1 and compute it in full detail. At higher orders in the anomaly coefficient, we expect a priori that further deformations of the BRST rules are necessary.

Interior product, Lie derivative and Wilson line in the KBc subsector of open string field theory

The open string field theory of Witten (SFT) has a close formal similarity with Chern-Simons theory in three dimensions. This similarity is due to the fact that the former theory has concepts corresponding to forms, exterior derivative, wedge product and integration over the manifold. In this paper, we introduce the interior product and the Lie derivative in the KBc subsector of SFT. The interior product in SFT is specified by a two-component “tangent vector” and lowers the ghost number by one (like the ordinary interior product maps a p-form to (p − 1)-form). The Lie derivative in SFT is defined as the anti-commutator of the interior product and the BRST operator. The important property of these two operations is that they respect the KBc algebra.Deforming the original (K, B, c) by using the Lie derivative, we can consider an infinite copies of the KBc algebra, which we call the KBc manifold. As an application, we construct the Wilson line on the manifold, which could play a role in reproducing degenerate fluctuation modes around a multi-brane solution.

Renormalization and mixing of the Gluino-Glue operator on the lattice

We study the mixing of the Gluino-Glue operator in mathcal{N}=1 Supersymmetric Yang–Mills theory (SYM), both in dimensional regularization and on the lattice. We calculate its renormalization, which is not merely multiplicative, due to the fact that this operator can mix with non-gauge invariant operators of equal or, on the lattice, lower dimension. These operators carry the same quantum numbers under Lorentz transformations and global gauge transformations, and they have the same ghost number. We compute the one-loop quantum correction for the relevant two-point and three-point Green’s functions of the Gluino-Glue operator. This allows us to determine renormalization factors of the operator in the {overline{mathrm{MS}}} scheme, as well as the mixing coefficients for the other operators. To this end our computations are performed using dimensional and lattice regularizations. We employ a standard discretization where gluinos are defined on lattice sites and gluons reside on the links of the lattice; the discretization is based on Wilson’s formulation of non-supersymmetric gauge theories with clover improvement. The number of colors, N_c, the gauge parameter, beta , and the clover coefficient, c_{mathrm{SW}}, are left as free parameters.

Superspace formulation of exotic supergravities in six dimensions

We provide a linearised superfield description of the exotic non-metric N = (4, 0) supergravity in D = 6, by using a pure spinor superfield formalism. The basic field Ψ is a ghost number 2 scalar, transforming in the same R-symmetry module as the tensor fields. Partial results for the N = (1, 3) model are presented.

Notes on the 11D pure spinor wordline vertex operators

The construction of the ghost number zero and one vertex operators for the 11D pure spinor superparticle will be revisited. In this sense, an alternative way of defining the ghost number one vertex operator will be given after introducing a ghost number -2 operator made out of physical operators defined on the 11D non-minimal pure spinor superspace. This procedure will make explicit and transparent the relation between the ghost number three and one vertex operators. In addition, using a non-Lorentz covariant b-ghost, ghost number zero and two vertex operators satisfying standard descent equations will be presented in full form.

Policies Against Tax Evasion Through Ocupational Choice

This paper presents a model of tax evasion with endogenous labor supply in which underreporting in one sector is possible but impossible in another. In addition, there is an unregistered sector where no one reports their earnings to the tax office. We found that the effects on the number of evaders and tax ghosts become more robust and conclusive than those on hours of unreported work usually considered by the literature. Moreover, our results are supported by abundant econometric studies, thereby eliminating current discrepancies between the theoretical framework in the tradition of Allingham and Sandmo (1972) and empirical evidence. Surprisingly, most of the measures that are effective against tax evasion in the registered sectors expand the unregistered sector. To solve this we propose both coercive measures to be applied mainly in the unregistered sector and policies aimed at improving moral attitudes against evasion and productivity rates in the aboveground economy.

Echocardiographic assessment of residuals after transvenous intracardiac lead extraction

Detection of residual fibrotic tissue, called ghosts, after lead extraction is a new phenomenon in cardiology. This paper aims at describing the phenomenon of ghosts and determining their characteristic features. The study group consisted of 580 consecutive patients who underwent transvenous lead extraction (TLE) due to local infection, endocarditis and a superfluous lead. Each patient was clinically examined with the application of transthoracic echocardiography and transesophageal echocardiography directly before and after TLE. In the study population ghosts were detected in 110 patients (19%), and in 470 cases (81%) fibrotic tissue residuals were not found. Ghosts were most often located along the originally implanted lead's route. Longer ghosts were found after the removal of cardiac resynchronization therapy (CRT) and dual chamber pacing (DDD) devices. The local infection and infective endocarditis are associated with a larger number of ghosts revealed after the removal procedure (p = 0.006). The type of the implanted device: CRT/ICD/double chamber pacemaker/single chamber pacemaker, similar to the number of leads, did not impact on the number of the detected ghosts. The relationship between abrasions of the leads and the presence of ghosts proved significant, however (p = 0.043). TLE is associated with the presence of fibrotic tissue residuals in approx. 19% of patients. Indications for lead extraction due to local infection and endocarditis yielded significantly more cases of ghosts than in the entire patient population. The presence of abrasions is a good predictor for the presence of ghosts on the leads.

Notes on the D = 11 pure spinor superparticle

The D = 11 pure spinor superparticle has been shown to describe linearized D = 11supergravityinamanifestlycovariantway. Anumberofauthorshaveproposedthat its correlation functions be used to compute amplitudes. The use of the scalar structure of the eleven-dimensional pure spinor top cohomology introduces a natural measure for computing such correlation functions. This prescription requires the construction of ghost number one and zero vertex operators. In these notes, we construct explicitly a ghost number one vertex operator but show the incompatibiliy of a ghost number zero vertex operator satisfying a standard descent equation for D = 11 supergravity.

L_{infty } Algebras for Extended Geometry from Borcherds Superalgebras

We examine the structure of gauge transformations in extended geometry, the framework unifying double geometry, exceptional geometry, etc. This is done by giving the variations of the ghosts in a Batalin–Vilkovisky framework, or equivalently, an L_infty algebra. The L_infty brackets are given as derived brackets constructed using an underlying Borcherds superalgebra {mathscr {B}}({{mathfrak {g}}}_{r+1}), which is a double extension of the structure algebra {{mathfrak {g}}}_r. The construction includes a set of “ancillary” ghosts. All brackets involving the infinite sequence of ghosts are given explicitly. All even brackets above the 2-brackets vanish, and the coefficients appearing in the brackets are given by Bernoulli numbers. The results are valid in the absence of ancillary transformations at ghost number 1. We present evidence that in order to go further, the underlying algebra should be the corresponding tensor hierarchy algebra.

Hamiltonian BRST formalism for gauge fields on black hole spacetimes

We investigate the Becchi-Rouet-Stora-Tyutin (BRST) formalism for gauge theories on spherically symmetric black hole spacetimes, with or without a cosmological constant ($\Lambda\geq0$). This is illustrated through the example of scalar electrodynamics. We first demonstrate that the horizons contribute additional surface terms to the Gauss law constraint of the theory when gauge transformations are not required to vanish on the horizons. We then consider the BRST invariant path integral including these surface terms following the Hamiltonian BRST formalism. We fix a radiation-like gauge which involves null components of the electromagnetic field at the horizons. We find that the presence of the surface terms in the constraint forces the ghost and gauge fixing actions to include additional surface integrals at the horizons. The null combination of the gauge fields at the horizons is shown to modify the ghost number charge of the theory through additional terms at the horizons. We also demonstrate how one can construct a gauge-fixing fermion which generates its own nilpotent symmetry transformations, called co-BRST transformations, that leave the theory invariant. The BRST and co-BRST transformations are further used to identify dressed (gauge invariant) fields of theory, whose dressings are affected by the presence of Killing horizons. We conclude with a discussion of potential applications of our results in soft limits and thermal field theories on black hole backgrounds.