High Energy Physics Theory

A general framework is described which associates geometrical structures to any set ofDfinite-dimensional hermitian matricesXa, a=1,...,D. This framework generalizes and systematizes the well-known examples of fuzzy spaces, and allows to extract the underlying classical space without requiring the limit of large matrices or representation theory. The approach is based on the previously introduced concept of quasi-coherent states. In particular, a concept of quantum Kähler geometry arises naturally, which includes the well-known quantized coadjoint orbits such as the fuzzy sphereS2Nand fuzzyCPnN. A quantization map for quantum Kähler geometries is established. Some examples of quantum geometries which are not Kähler are identified, including the minimal fuzzy torus.

We show that the standard notion of entanglement is not defined for gravitationally anomalous two-dimensional theories because they do not admit a local tensor factorization of the Hilbert space into local Hilbert spaces. Qualitatively, the modular flow cannot act consistently and unitarily in a finite region, if there are different numbers of states with a given energy traveling in the two opposite directions. We make this precise by decomposing it into two observations: First, a two-dimensional CFT admits a consistent quantization on a space with boundary only if it is not anomalous. Second, a local tensor factorization always leads to a definition of consistent, unitary, energy-preserving boundary condition. As a corollary we establish a generalization of the Nielsen-Ninomiya theorem to all two-dimensional unitary local QFTs: No continuum quantum field theory in two dimensions can admit a lattice regulator unless its gravitational anomaly vanishes. We also show that the conclusion can be generalized to six dimensions by dimensional reduction on a four-manifold of nonvanishing signature. We advocate that these points be used to reinterpret the gravitational anomaly quantum-information-theoretically, as a fundamental obstruction to the localization of quantum information.

In this paper, we will obtain quantum work for a quantum scale five dimensional Myers-Perry black hole. It will be observed that at such short distances, the quantum work will be corrected by non-perturbative quantum corrections. We will use the Jarzynski equality to obtain this quantum work modified by non-perturbative corrections. These non-pertubative corrections will modify the stability of a quantum Myers-Perry black hole. We will define a quantum corrected information geometry by incorporating the non-perturbative quantum corrections in the information geometry of a Myers-Perry black hole. We will use several different quantum corrected effective information metrics to analyze the stability of a quantum Myers-Perry black hole.

Circuit Complexity, a well known computational technique has recently become the backbone of the physics community to probe the chaotic behaviour and random quantum fluctuations of quantum fields. This paper is devoted to the study of out-of-equilibrium aspects and quantum chaos appearing in the universe from the paradigm of two well known bouncing cosmological solutions viz.Cosine hyperbolicandExponentialmodels of scale factors. Besidescircuit complexity, we use theOut−of−Time Ordered correlation (OTOC)functions for probing the random behaviour of the universe both at early and the late times. In particular, we use the techniques of well known two-mode squeezed state formalism in cosmological perturbation theory as a key ingredient for the purpose of our computation. To give an appropriate theoretical interpretation that is consistent with the observational perspective we use the scale factor and the number of e-foldings as a dynamical variable instead of conformal time for this computation. From this study, we found that the period of post bounce is the most interesting one. Though it may not be immediately visible, but an exponential rise can be seen in thecomplexityonce the post bounce feature is extrapolated to the present time scales. We also find within the very small acceptable error range a universal connecting relation between Complexity computed from two different kinds of cost functionals-linearly weightedandgeodesic weightedwith the OTOC. Furthermore, from thecomplexitycomputation obtained from both the cosmological models and also using the well known MSS bound on quantum Lyapunov exponent,λ≤2π/βfor the saturation of chaos, we estimate the lower bound on the equilibrium temperature of our universe at late time scale. Finally, we provide a rough estimation of the scrambling time in terms of the conformal time.

It has been argued that generic classical perturbations to asymptotically de-Sitter Reissner-Nordtsröm (RN-dS) black holes may violate strong cosmic censorship conjecture. In this paper, we analyze whether quantum corrections can restore the conjecture. We study a quantum scalar field in RN-dS geometry and analyze the smoothness of a state across various horizons using the criteria developed in arXiv:1910.02992. Since de-Sitter black holes have a cosmological horizon, that typically radiates at a different temperature than the event horizon, the existence of a quantum state which is regular everywhere in the exterior region is non-trivial. We find such states for spherically symmetric black holes in arbitrary dimensions. We then demonstrate that such states are singular at the inner horizon of RN-dS black holes in various dimensions. Hence, quantum fluctuations are sufficient to restore the strong cosmic censorship conjecture in RN-dS.

We investigate macroscopic and microscopic quantum correlations in a heavy quark-gluon medium holographically. In order to represent heavy quarks, we consider the string cloud geometry which involves uniformly distributed open strings. In this system, the macroscopic quantum correlation is described by the entanglement entropy and increases when the gluon's excitation and the quark's density increase. We also investigate a microscopic two-point correlation of local operators in the quark-gluon medium. Our calculation shows that the two-point function of local operators decreases as the background entanglement entropy increases. This is because the strong quantum correlation of the background medium gives rise to a strong screening effect. Furthermore, we survey the effect of the quark-gluon medium on the quark-antiquark pair by employing the holographic Wilson loop.

We argue, in the context of Ads/CFT correspondence, that the degree of entanglement on the CFTs side determines the orientation of space and time on the dual global spacetime. That is, the global spacetime dual to entangled copies of field theory is non-orientable, while the product state of the CFTs results in an orientable spacetime. As a result, disentangling the degrees of freedom between two copies of CFT implies, on the gravity side, the transition from a non-orientable spacetime to a spacetime having a definite orientation of space and time, thus an orientable spacetime. We conclude showing that topology change induced by decreasing the entanglement between two sets of degrees of freedom corresponds to a topological blow down operation.

We study in detail various information theoretic quantities with the intent of distinguishing between different charged sectors in fractionalized states of large-Ngauge theories. For concreteness, we focus on a simple holographic(2+1)-dimensional strongly coupled electron fluid whose charged states organize themselves into fractionalized and coherent patterns at sufficiently low temperatures. However, we expect that our results are quite generic and applicable to a wide range of systems, including non-holographic. The probes we consider include the entanglement entropy, mutual information, entanglement of purification and the butterfly velocity. The latter turns out to be particularly useful, given the universal connection between momentum and charge diffusion in the vicinity of a black hole horizon. The RT surfaces used to compute the above quantities, though, are largely insensitive to the electric flux in the bulk. To address this deficiency, we propose a generalized entanglement functional that is motivated through the Iyer-Wald formalism, applied to a gravity theory coupled to aU(1)gauge field. We argue that this functional gives rise to a coarse grained measure of entanglement in the boundary theory which is obtained by tracing over (part) of the fractionalized and cohesive charge degrees of freedom. Based on the above, we construct a candidate for an entropicc-function that accounts for the existence of bulk charges. We explore some of its general properties and their significance, and discuss how it can be used to efficiently account for charged degrees of freedom across different energy scales.

We study a class of perturbative scalar quantum field theories where dynamics is characterized by Lorentz-invariant or Lorentz-breaking non-local operators of fractional order and the underlying spacetime has a varying spectral dimension. These theories are either ghost free or power-counting renormalizable but they cannot be both at the same time. However, some of them are one-loop unitary and finite, and possibly unitary and finite at all orders.

In recent work, it was argued that quantum computations with inputs and outputs distributed in spacetime, or quantum tasks, impose constraints on entanglement in holographic theories. The resulting constraint was named the connected wedge theorem and can verified by a direct bulk proof using focusing arguments in general relativity. In this article we extend this work to the context of AdS/BCFT, where an end-of-the-world brane is present in the bulk. By considering quantum tasks which exploit information localized to the brane, we find a new connected wedge theorem. We apply this theorem to brane models of black holes, where it relates the formation of islands in the Ryu-Takayanagi formula to causal features of the ambient spacetime. In particular, we find that if the black hole interior is causally connected to the radiation system through the ambient spacetime, then an island forms. For constant tension branes in pure AdS the converse also holds.