arXiv subjects

Jerzy Kowalski-Glikman

Publications and source records attributed to Jerzy Kowalski-Glikman.

At least 19 recordsLinked to original sources

arXiv2026

Bias in Local Spin Measurements from Deformed Symmetries

We study local spin measurements on bipartite singlet states when rotational symmetry is described by a quantum group rather than an ordinary Lie group. Although the fundamental spin-1/2 representation has the usual one-particle action on states, the non-trivial coproduct selects a deformed analogue of the Bell singlet state. We show that conventional tensor-factor measurements on this invariant singlet lead to deformation-dependent one-site outcome statistics. We then compare this standard-local prescription with a braided-local one, obtained by dressing local observables with the R-matrix and using the corresponding braided inner product. The braided observables are covariant under the Hopf adjoint action, but define a distinct measurement structure and lead to the reciprocal bias on the deformed singlet state.

quant-ph↗

arXiv2026

From the Corner Proposal to the Area Law

We provide an explicit realization of the Corner Proposal for Quantum Gravity in the case of spherically symmetric spacetimes in four dimensions, or equivalently, two-dimensional dilaton gravity. We construct coherent states of the Quantum Corner Symmetry group and compute the entanglement entropy relative to these states. We derive the classical corner charges and relate them to operator expectation values in coherent states. For a subset of coherent states that we call classical states, we find that the entanglement entropy exhibits a leading term proportional to the area, recovering the Bekenstein-Hawking area law in the semiclassical limit.

hep-th↗

arXiv2026

Quantum Geometry from Area Fluctuations

We construct a quantum-statistical analogue of Einstein's fluctuation argument for black-body radiation in the context of causal-diamond geometry. Starting from the phase space of a stretched horizon inside a Minkowski causal diamond, we quantize the Poisson algebra generated by the fields averaged over stretched-horizon time. We then compute the fluctuations of the averaged area density of the transverse two-spheres in a thermal state constructed in analogue with the black-body thermal state. In the null limit, where the stretched horizon approaches the causal-diamond boundary, this yields a thermal fluctuation formula of the boundary area operator that contains two terms, in direct analogue with the black-body radiation. The term quadratic in the expectation value is the ``classical'' contribution, while the linear term has the Verlinde--Zurek scaling characteristic of independent microscopic constituents. In direct analogue with Einstein's interpretation of black-body energy fluctuations as evidence for light quanta, we interpret the linear area-fluctuation term as a statistical signature of discrete quanta of geometry. This provides bottom-up evidence for quantum area degrees of freedom and supports the embadon picture of null quantum geometry.

hep-th↗

arXiv2026

κ-deformed spin-1/2 field

In this paper, we investigate the Poincaré and discrete symmetries of a $κ$-deformed spin-$\tfrac12$ field, extending recent results obtained for scalar fields. We construct an action that is Poincaré invariant and analyze its consequences within the deformed framework. Our results confirm the findings of our recent analysis of the $κ$-deformed scalar field, where we established that there is no action invariant under both Poincaré symmetry and charge conjugation in the $κ$-deformed case, while $\mathcal{CPT}$-symmetry can be restored through a natural deformation of time reversal. Furthermore, we present an explicit calculation of the Noether charges associated with Poincaré symmetry and show that their algebra closes, demonstrating the internal consistency of the theory.

hep-th↗

arXiv2026

Charges of supergravity

We study conserved charges of $\mathcal{N}=1$ supergravity formulated as a constrained BF theory based on the $\OSp(1|4)$ superalgebra. Using the covariant phase space formalism, we derive bulk and boundary contributions to the symplectic structure and construct charges associated with Lorentz transformations, supersymmetry, translations, and diffeomorphisms. We show that the algebra of boundary charges reproduces the expected superalgebra, while translational charges vanish on-shell due to the super-torsion constraint, leaving Lorentz and supersymmetry as the non-trivial generators.

hep-th↗

arXiv2026

On the non-commutativity of geometric observables in different Lorentz frames

Our aim is to establish whether geometric observables, such as length, area or volume of a physical object, viewed by different observers Poisson commute or not. To illustrate this, we compute the Poisson bracket of two lengths associated to a rigid rod and measured by two different geodesic (inertial) observers, one of which is at rest while the other is moving with respect to the rod. Our calculation shows that geometric observables measured by different observers generically do not Poisson commute, not even in Minkowski spacetime. This non-trivial result provides interesting insights into questions related to the presence of a fundamental scale in the context of quantum gravity.

gr-qc↗

arXiv2026

Asymmetry in momentum space: restoring ${\cal C}{\cal P}{\cal T}$ invariance of $κ$-field theory

The positive and negative energy modes of a field theory in $κ$-Minkowski/$κ$-Poincaré noncommutative spacetime have very different symmetry properties. This can be understood geometrically by considering that they span two distinct sectors of a curved momentum space. By performing an explicit direct computation of the relativistic Noether charges and their algebra within the canonical formalism, we identify a striking consequence of this asymmetry in momentum space: charge conjugation and Poincaré invariance are incompatible. We then notice how the structure of momentum space suggests that time reversal could be deformed so that the overall ${\cal C}{\cal P}{\cal T}$-invariance is restored. We prove that this new proposal works by studying the transformation properties under deformed discrete symmetries of the new relativistic charges.

hep-th↗

arXiv2025

Entanglement Entropy of Quantum Corners

In gravitational theories with boundaries, diffeomorphisms can become physical and acquire a non-vanishing Noether charge. Using the covariant phase space formalism, on shell of the gravitational constraints, the latter localizes on codimension-$2$ surfaces, the corners. The corner proposal asserts that these charges, and their algebras, must be important ingredients of any quantum gravity theory. In this manuscript, we continue the study of quantum corner symmetries and algebras by computing the entanglement entropy and quantum informational properties of quantum states abiding to the quantum representations of corners in the framework of $2$-dimensional gravity. We do so for two classes of states: the vacuum and coherent states, properly defined. We then apply our results to JT gravity, seen as the dimensional reduction of $4$d near extremal black holes. There, we demonstrate that the entanglement entropy of some coherent quantum gravity states -- states admitting a semiclassical description -- scales like the dilaton, reproducing the semiclassical area law behavior and further solidifying the quantum informational nature of entropy of quantum corners. We then study general states and their gluing procedure, finding a formula for the entanglement entropy based entirely on the representation theory of $2$d quantum corners.

hep-th↗

arXiv2025

Quantum Corner Symmetry: Representations and Gluing

The corner symmetry algebra organises the physical charges induced by gravity on codimension-$2$ corners of a manifold. In this letter, we initiate a study of the quantum properties of this group using as a toy model the corner symmetry group of two-dimensional gravity $\mathrm{SL}\left(2,\mathbb{R}\right)\ltimes \mathbb{R}^2$. We first describe the central extensions and how the quantum corner symmetry group arises and give the Casimirs. We then make use of one particular representation to discuss the gluing of corners, achieved by identifying the maximal commuting sub-algebra. This is a concrete implementation of the gravitational constraints at the quantum level.

hep-th↗

arXiv2024

On Carrollian and Galilean contractions of BMS algebra in 3 and 4 dimensions

In this paper, we find a class of Carrollian and Galilean contractions of (extended) BMS algebra in 3+1 and 2+1 dimensions. To this end, we investigate possible embeddings of 3D/4D Poincaré into the BMS${}_3$ and BMS${}_4$ algebras, respectively. The contraction limits in the 2+1-dimensional case are then enforced by appropriate contractions of its Poincaré subalgebras. In 3+1 dimensions, we have to apply instead the analogy between the structures of Poincaré and BMS algebra. In the case of non-vanishing cosmological constant in 2+1 dimensions, we consider the contractions of $Λ$-BMS${}_3$ algebra in an analogous manner.

hep-th↗

arXiv2024

On the covariant formulation of gauge theories with boundaries

In the present article, we review the classical covariant formulation of Yang-Mills theory and general relativity in the presence of spacetime boundaries, focusing mainly on the derivation of the presymplectic forms and their properties. We further revisit the introduction of the edge modes and the conditions which justify them, in the context where only field-independent gauge transformations are considered. We particularly show that the presence of edge modes is not justified by gauge invariance of the presymplectic form, but rather by the condition that the presymplectic form is degenerate on the initial field space, which allows to relate this presymplectic form to the symplectic form on the gauge reduced field space via pullback.

hep-th↗

arXiv2024

Deformation-induced CPT violation in entangled pairs of neutral kaons

In this paper we consider description of kaon -- anti-kaon interference in the context of a theory with deformed $\cal CPT$ symmetry. In the case of such theoretical models, deviations from the standard $\cal CPT$ invariance is related to the momentum carried by the particles; in particular the rest masses of particles and antiparticles are equal. We find that the decay intensity of kaon -- anti-kaon pair has three contributing terms: the correct-parity, the wrong-parity, and the interference between them, all of which are affected by deformation. Using the fact that the presence of such terms were not observed we estimate the magnitude of deformation parameter $κ\gtrsim 10^{18}$ GeV, very close to the expected Planck mass scale. This raises hopes that the effect, if exists, could be detected in a near future accelerator experiments. An uncertainty of the energy measurement is crucial for accuracy of these predictions.

hep-ph↗

arXiv2023

Quantum Gravity Phenomenology and Particle Physics

Quantum gravity phenomenology has been historically regarded as a difficult endeavour, due to the apparent scarcity of phenomena involving the required scales of length (Planck length $l_P$) and energy (Planck energy $E_P$). It was realized, however, that one can look for cumulative effects of a quantum theory of gravity at energies $E/E_P \ll 1$ if even tiny effects are amplified by the large time of flight or very high energies, common to astrophysical phenomena. In the this work, complementary to the COST action CA18108 White Book, we put forward a proposal that quantum gravity phenomenology can be fruitfully pursued also with the help of terrestrial particles accelerators. We first discuss the theoretical background, and then concentrate on deformed discrete symmetries C,P,T. We investigate possible experimental signatures of CPT deformation, particularly concerning the difference in decay time between particles and antiparticles, and fields interference.

hep-ph↗

arXiv2023

Finite $κ$-deformed two-particle boost

In this paper we consider the \k{appa}-deformed boost acting on a two-particles states. Using techniques developed in the case of infinitesimal boost we compute explicit expression for the components of the finite boost matrices acting on the first and second particle. We briefly discuss phenomenological consequences of our findings.

hep-th↗

arXiv2023

The Vacuum Energy Density and Gravitational Entropy

The failure to calculate the vacuum energy is a central problem in theoretical physics. Presumably the problem arises from the insistent use of effective field theory reasoning in a context that is well beyond its intended scope. If one follows this path, one is led inevitably to statistical or anthropic reasoning for observations. It appears that a more palatable resolution of the vacuum energy problem requires some form of UV/IR feedback. In this paper we take the point of view that such feedback can be thought of as arising by defining a notion of quantum space-time. We reformulate the regularized computation of vacuum energy in such a way that it can be interpreted in terms of a sum over elementary phase space volumes, that we identify with a ground state degeneracy. This observation yields a precise notion of UV/IR feedback, while leaving a scale unfixed. Here we argue that holography can be thought to provide a key piece of information: we show that equating this microscopic ground state degeneracy with macroscopic gravitational entropy yields a prediction for the vacuum energy that can easily be consistent with observations. Essentially, the smallness of the vacuum energy is tied to the large size of the Universe. We discuss how within this scenario notions of effective field theory can go so wrong.

hep-th↗

arXiv2023

On the Inevitable Lightness of Vacuum

In this essay, we present a new understanding of the cosmological constant problem, built upon the realization that the vacuum energy density can be expressed in terms of a phase space volume. We introduce a UV-IR regularization which implies a relationship between the vacuum energy and entropy. Combining this insight with the holographic bound on entropy then yields a bound on the cosmological constant consistent with observations. It follows that the universe is large, and the cosmological constant is naturally small, because the universe is filled with a large number of degrees of freedom.

hep-th↗

arXiv2022

Quantum particles in non-commutative space-time: an identity crisis

We argue that the notion of identical particles is no longer well defined in quantum systems governed by non-commutative deformations of space-time symmetries. Such models are characterized by four-momentum space given by a non-abelian Lie group. Our analysis is based on the observation that, for states containing more than one particle, only the total momentum of the system is a well defined quantum number. Such total momentum is obtained from the non-abelian composition of the particles individual momenta which are no longer uniquely defined. The main upshot of our analysis is that all previous attempts to construct Fock spaces for these models rested on wrong assumptions and indeed have been unsuccessful. We also show how the natural braiding of momentum quantum numbers which characterizes the exchange of factors in the tensor product of states is covariant under relativistic transformations thus solving a long standing problem in the field.

hep-th↗

arXiv2022

A group theoretic description of the $κ$-Poincaré Hopf algebra

It is well known in the literature that the momentum space associated to the $κ$-Poincaré algebra is described by the Lie group $\mathsf{A}\mathsf{N}(3)$. In this letter we show that the full $κ$-Poincaré Hopf algebra structure can be obtained from rather straightforward group-theoretic manipulations starting from the Iwasawa decomposition of the of the $\mathsf{SO(1,4)}$ group.

hep-th↗