We discuss the scattering of massive scalar probes off Myers-Perry black holes in the Kerr-Schild gauge. Extending the analysis performed recently for Kerr(-Newman) black holes, we show that the Kerr-Schild gauge allows to write down the tree-level scattering amplitude for Myers-Perry black holes in analytic form. For generic values of the angular momenta, Myers-Perry solutions have a richer multipolar structure compared to their four-dimensional counterparts, because they are characterized by the presence of stress multipoles, together with the more familiar mass and current multipoles. By focusing on the five-dimensional case, we derive the leading eikonal phase from the scattering amplitude and we give an explicit expression for two limiting scenari, namely when the two angular momenta are the same, so that the mass multipoles vanish but still the solution has a non-vanishing stress quadrupole and a current dipole, and when one of the two angular momenta is zero, and correspondingly the stress multipoles vanish similar to the Kerr case.

Italy

Massimo Bianchi

Claudio Gambino

Fabio Riccioni

Vincenzo Zevola

Probing the multipolar structure of Myers-Perry black holes with scattering amplitudes

We investigate the quasinormal modes of massive scalar fields in the background of five-dimensional Myers-Perry black holes. In particular, we explore the case for Myers-Perry black holes with two arbitrary rotation parameters. Since the Klein-Gordon equation for the scalar field is separable, we numerically compute the scalar quasinormal modes by using the radial and angular equations. Two methods, the continued fraction method and matrix method, are used in the numerical calculation. We find that all obtained modes have negative imaginary parts and are decaying modes. We also consider the impact of the rotation parameters, scalar field mass <italic>&#956;</italic> and azimuthal numbers on the scalar quasinormal modes. Besides, when the scalar mass <italic>&#956;</italic> becomes relatively large, we also find the long-living scalar modes. Our numerical results also demonstrate the symmetries of the QNMs explicitly.

China

Zi-Yang Huang

Jia-Hui Huang

Quasinormal modes of massive scalar fields in five-dimensional Myers-Perry black holes with two arbitrary rotation parameters

What does a black hole look like? In 1 + 3 spacetime dimensions, the optical appearance of a black hole is a bidimensional region in the observer’s sky often called the black hole shadow, as supported by the EHT observations. In higher dimensions this question is more subtle and observational setup dependent. Previous studies considered the shadows of higher dimensional black holes to remain bidimensional. We argue that the latter should be regarded as a tomography of a higher dimensional structure, the $\textit{hypershadow}$, which would be the structure “seen” by higher dimensional observers. As a case study we consider the cohomogeneity-one Myers-Perry black hole in 1 + 4 dimensions, and compute its tridimensional hypershadow.

Portugal

João Novo

Pedro Cunha

Carlos Herdeiro

Hypershadows of higher dimensional black objects: a case study of cohomogeneity-one d=5 Myers-Perry

We investigate the nonlinear dynamics of D = 2N + 3 Myers-Perry black holes with almost equal angular momenta, which have N equal spins out of possible N + 1 spins. In particular, we study the ultraspinning instability and the fate of its nonlinear evolution using the large D effective theory approach. We find that every stationary phase can be mapped to the counterpart in the singly rotating phase within the leading order effective theory. From the known results of singly rotating solutions, we obtain the phase diagram of almost equally rotating black holes. We also obtain a certain implication for the possible topology changing transition.

Japan

Ryotaku Suzuki

Shinya Tomizawa

Dynamics of Myers-Perry black holes with almost equal angular momenta in odd dimensions

The near-zone “Love” symmetry resolves the naturalness issue of black hole Love number vanishing with SL (2, ℝ) representation theory. Here, we generalize this proposal to 5-dimensional asymptotically flat and doubly spinning (Myers-Perry) black holes. We consider the scalar response of Myers-Perry black holes and extract its static scalar Love numbers. In agreement with the naturalness arguments, these Love numbers are, in general, non-zero and exhibit logarithmic running unless certain resonant conditions are met; these conditions include new cases with no previously known analogs. We show that there exist two near-zone truncations of the equations of motion that exhibit enhanced SL (2, ℝ) Love symmetries that explain the vanishing of the static scalar Love numbers in the resonant cases. These Love symmetries can be interpreted as local SL (2, ℝ) SL (2, ℝ) near-zone symmetries spontaneously broken down to global SL (2, ℝ) × U (1) symmetries by the periodic identification of the azimuthal angles. We also discover an infinite-dimensional extension of the Love symmetry into SL (2, ℝ)   <math> <mo>⋉</mo> <mover> <mi>U</mi> <mo>̂</mo> </mover> <msubsup> <mfenced> <mn>1</mn> </mfenced> <mi>V</mi> <mn>2</mn> </msubsup> </math>  $$ \ltimes \hat{U}{(1)}_{\mathcal{V}}^2 $$  that contains both Love symmetries as particular subalgebras, along with a family of SL (2, ℝ) subalgebras that reduce to the exact near-horizon Myers-Perry black hole isometries in the extremal limit. Finally, we show that the Love symmetries acquire a geometric interpretation as isometries of subtracted (effective) black hole geometries that preserve the internal structure of the black hole and interpret these non-extremal SL (2, ℝ) structures as remnants of the enhanced isometry of the near-horizon extremal geometries.

United States

Panagiotis Charalambous

Mikhail Ivanov

Scalar Love numbers and Love symmetries of 5-dimensional Myers-Perry black holes

The successful transition from core-collapse supernova simulations using classical neutrino transport to simulations using quantum neutrino transport will require the development of methods for calculating neutrino flavor transformations that mitigate the computational expense. One potential approach is the use of angular moments of the neutrino field, which has the added appeal that there already exist simulation codes which make use of moments for classical neutrino transport. Evolution equations for quantum moments based on the quantum kinetic equations can be straightforwardly generalized from the evolution of classical moments based on the Boltzmann equation. We present an efficient implementation of neutrino transformation using quantum angular moments in the free streaming, spherically symmetric bulb model. We compare the results against analytic solutions and the results from more exact multiangle neutrino flavor evolution calculations. We find that our moment-based methods employing scalar closures predict, with good accuracy, the onset of collective flavor transformations seen in the multiangle results. However in some situations they overestimate the coherence of neutrinos traveling along different trajectories. More sophisticated quantum closures may improve the agreement between the inexpensive moment-based methods and the multiangle approach.

McKenzie Myers

Theo Cooper

MacKenzie Warren

Jim Kneller

Gail McLaughlin

Sherwood Richers

Evan Grohs

Carla Fröhlich

Neutrino flavor mixing with moments

We investigate the separability of the Klein-Gordon equation on near horizon of <math><mrow><mi>d</mi></mrow></math>-dimensional rotating Myers-Perry black hole in two limits: (i) generic extremal case and (ii) extremal vanishing horizon case. In the first case, there is a relation between the mass and rotation parameters so that black hole temperature vanishes. In the latter case, one of the rotation parameters is restricted to zero on top of the extremality condition. We show that the Klein-Gordon equation is separable in both cases. Also, we solved the radial part of that equation and discuss its behavior in small- and large-<math><mrow><mi>r</mi></mrow></math> regions.

Iran

Saeedeh Sadeghian

Armenia

Hovhannes Demirchian

Separability of Klein-Gordon equation on near horizon extremal Myers-Perry black hole

In this paper, we will obtain quantum work for a quantum scale five dimensional Myers-Perry black hole. Unlike heat represented by Hawking radiation, the quantum work is represented by a unitary information preserving process, and becomes important for black holes only at small quantum scales. It will be observed that at such short distances, the quantum work will be corrected by non-perturbative quantum gravitational corrections. We will use the Jarzynski equality to obtain this quantum work modified by non-perturbative quantum gravitational corrections. These non-perturbative corrections will also 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.

Canada

Behnam Pourhassan

Salman Wani

Saheb Soroushfar

Mir Faizal

Quantum work and information geometry of a quantum Myers-Perry black hole

This study investigates the stability of higher-dimensional singly rotating Myers-Perry–de Sitter (MP–dS) black holes against scalar field perturbations. The phase spaces of MP-dS black holes with one spin parameter are discussed. Additionally, the quasinormal modes (QNMs) of MP-dS black holes are calculated via the asymptotic iteration method and sixth-order Wentzel–Kramers–Brillouin approximation. For near-extremal MP-dS black holes, the event horizon may be considerably close to the cosmological horizon. In such cases, the Pöschl–Teller technique yields an accurate analytic formula for the QNMs. It is found that when the spin parameter of a black hole increases, the scalar perturbation modes oscillate at higher frequencies and decay faster. Furthermore, the MP-dS black hole with a single rotation is found to be stable under perturbation.

South Korea

Supakchai Ponglertsakul

Bogeun Gwak

Massive scalar perturbations on Myers-Perry–de Sitter black holes with a single rotation

We demonstrate separability of the dynamical equations for all p-form fluxes in the Myers-Perry-(A)dS geometry, extending the earlier results for electromagnetic field. In the physically important cases of p = (1–4), we explicitly write the ODEs governing the dynamics of separable solutions.

Oleg Lunin

Excitations of the Myers-Perry black holes