The nuclear properties of bismuth isotopes <math altimg='si12.svg'><mrow><mo>(</mo><mi>Z</mi><mo linebreak='goodbreak'>=</mo><mn>83</mn><mo>)</mo></mrow></math>, with just one valence proton above the closed spherical shell at <math altimg='si13.svg'><mrow><mi>Z</mi><mo linebreak='goodbreak'>=</mo><mn>82</mn></mrow></math>, are expected to be governed by a single unpaired proton. However, already in semimagic 209Bi <math altimg='si14.svg'><mrow><mo>(</mo><mi>Z</mi><mo linebreak='goodbreak'>=</mo><mn>83</mn></mrow></math>, <math altimg='si15.svg'><mrow><mi>N</mi><mo linebreak='goodbreak'>=</mo><mn>126</mn><mo>)</mo></mrow></math>, the magnetic moment ( <italic>&#956;</italic>) strongly deviates from the single-particle Schmidt value. A near linear decrease in <italic>&#956;</italic> with the increase of <italic>N</italic> after the <math altimg='si4.svg'><mrow><mi>N</mi><mo linebreak='goodbreak'>=</mo><mn>126</mn></mrow></math> magic number was observed up to <math altimg='si16.svg'><mrow><mi>N</mi><mo linebreak='goodbreak'>=</mo><mn>130</mn></mrow></math>. In order to test whether this trend is kept at <italic>N</italic>&#8239;&gt;&#8239;130 and to reveal the underlying mechanisms, an investigation of 215,217Bi <math altimg='si17.svg'><mrow><mo>(</mo><mi>N</mi><mo linebreak='goodbreak'>=</mo><mn>132</mn><mo>,</mo><mn>134</mn><mo>)</mo></mrow></math> has been undertaken. The magnetic dipole and electric quadrupole moments of the <math altimg='si5.svg'><mrow><msup><mi>I</mi><mi>&#960;</mi></msup><mo linebreak='goodbreak'>=</mo><mn>9</mn><mo linebreak='goodbreak'>/</mo><msup><mn>2</mn><mo>&#8722;</mo></msup></mrow></math> nuclear ground states in these isotopes have been measured for the first time using the in-source resonance-ionization spectroscopy technique at ISOLDE (CERN). It has been shown that the linearly decreasing trend of <italic>&#956;</italic>( 209,211,213Bi <italic>g</italic>) is broken in 215,217Bi with a nearly constant value of <italic>&#956;</italic> observed. Experimental data have been compared to calculations in the framework of the configuration-interaction shell model with the monopole-based universal V <inf>MU</inf>+LS interaction. The peculiarities in the behavior of <italic>&#956;</italic>(Bi, <math altimg='si18.svg'><mrow><mn>9</mn><mo linebreak='goodbreak'>/</mo><msup><mn>2</mn><mo>&#8722;</mo></msup></mrow></math>) with increasing neutron number are explained as being due to the shell evolution, change of the neutron orbitals occupancies and strong configuration mixing beyond <math altimg='si16.svg'><mrow><mi>N</mi><mo linebreak='goodbreak'>=</mo><mn>130</mn></mrow></math>. Also, the difference in the <italic>&#956;</italic> trends for bismuth <math altimg='si12.svg'><mrow><mo>(</mo><mi>Z</mi><mo linebreak='goodbreak'>=</mo><mn>83</mn><mo>)</mo></mrow></math> and astatine <math altimg='si19.svg'><mrow><mo>(</mo><mi>Z</mi><mo linebreak='goodbreak'>=</mo><mn>85</mn><mo>)</mo></mrow></math> isotopes with <italic>N</italic>&#8239;&gt;&#8239;126 are reproduced by the shell-model calculations. It is shown that monopole interaction plays noticeable role in the description of the peculiarities of the <italic>&#956;</italic> behaviour. Additionally, the extension of the application of the V <inf>MU</inf> interaction to the <italic>&#956;</italic> isotopic trends for heavy nuclei is important for further study of the capabilities of this promising version of the shell-model calculations.

United Kingdom

A.N. Andreyev

A. Barzakh

M.D. Seliverstov

Z. Yue

China

Menglan Liu

Cenxi Yuan

Spain

Hungary

A. Algora

Slovakia

B. Andel

S. Antalic

Oman

M. Al Monthery

Germany

Switzerland

D. Atanasov

J. Benito

Italy

G. Benzoni

T. Berry

M.L. Bissell

K. Blaum

M.J.G. Borge

K. Chrysalidis

Romania

C. Clisu

Belgium

T.E. Cocolios

C. Costache

J.G. Cubiss

Canada

T. Day Goodacre

G.J. Farooq-Smith

D.V. Fedorov

V.N. Fedosseev

L.M. Fraile

Denmark

H.O.U. Fynbo

V. Gadelshin

L.P. Gaffney

United States

R. F Garcia Ruiz

C. Granados

Finland

P.T. Greenlees

R.D. Harding

L.J. Harkness-Brennan

R. Heinke

A. Herlert

M. Huyse

A. Illana

J. Jolie

D.S. Judson

Sweden

J. Karls

J. Konki

P. Larmonier

I. Lazarus

D. Leimbach

R. Lică

Z. Liu

France

D. Lunney

K.M. Lynch

M. Madurga

V. Manea

N. Marginean

R. Marginean

B.A. Marsh

C. Mihai

P. Molkanov

P. Mosat

M. Mougeot

J.R. Murias

E. Nacher

A. Negret

D. Neidherr

L. Nies

R.D. Page

S. Pascu

A. Perea

V. Pucknell

P. Rahkila

C. Raison

E. Rapisarda

K. Rezynkina

Japan

M. Rosenbush

R.E. Rossel

S. Rothe

V. Sánchez-Tembleque

K. Schomacker

L. Schweikhard

C. Seiffert

S. Sels

C. Sotty

L. Stan

M. Stryjczyk

D. Studer

J. Sundberg

C. Sürder

O. Tengblad

P. Van Duppen

V. Vedia

M. Verlinde

S. Viñals

N. Warr

A. Welker

F. Wienholtz

Australia

R.N. Wolf

Electromagnetic moments of 215,217Bi: Probing shell evolution beyond <math altimg='si4.svg'><mrow><mi>N</mi><mo linebreak='goodbreak'>=</mo><mn>126</mn></mrow></math>

Quantum computers are emerging technologies expected to become important tools for exploring various aspects of fundamental physics in the future. Therefore, we pose the question of whether quantum computers can help us to study the Page curve and the black hole information dynamics, which has been a key focus in fundamental physics. In this regard, we rigorously examine the qubit transport model, a toy qubit model of black hole evaporation on IBM’s superconducting quantum computers, to shed light on this question. Specifically, we implement the quantum simulation of the scrambling dynamics in black holes using an efficient random unitary circuit. Furthermore, we employ the swap-based many-body interference protocol and the randomized measurement protocol to measure the entanglement entropy of Hawking radiation qubits in this model. Finally, by incorporating quantum error mitigation techniques into our challenging implementation of entanglement entropy measurement protocols on the IBM quantum hardware, we accurately determine the Rényi entropy in the qubit transport model, thus showcasing the utility of quantum computers for future investigations of complex quantum systems.

Bangladesh

Talal Ahmed Chowdhury

Kwangmin Yu

Muhammad Asaduzzaman

Raza Sabbir Sufian

Capturing the Page curve and entanglement dynamics of black holes in quantum computers

The present work delves into probing the importance of mutual information of relevant subsystems in obtaining the correct time-evolution of fine-grained entropy of Hawking radiation, as suggested by Page. This was done by considering a functional renormalization group improved or simply, quantum corrected Schwarzschild black solution which captures the flavour of an effective theory of quantum gravity. The mentioned black hole solution emerges from an asymptotically safe average effective action which describes a trajectory in momentum-space and satisfies a renormalization group equation. Furthermore, in the before Page time scenario, the behaviour of the mutual information between appropriate subsystems over time leads to the Hartman–Maldacena time. The observations made for the quantum corrected Schwarzschild black hole have been compared to the same made for the standard Schwarzschild black hole in order to draw some novel conclusions. Based upon our observations, we also propose a formula for computing fine-grained entropy of Hawking radiation for an eternal black hole, in presence of the island.

India

Ashis Saha

Anirban Chowdhury

Sunandan Gangopadhyay

Investigating the role of mutual information in the Page curve for a functional renormalization group improved Schwarzschild black hole

This work employs the quantum extremal surface framework to compute the Page curve for black holes corrected by nonextensive entropy. The entropy of Hawking radiation increases linearly with time, leading to the persistence of the information paradox for nonextensive entropy-corrected black holes. At late time, we extremize the generalized entropy functional; incorporating contributions from both matter and the quantum extremal island, we establish that the entanglement entropy of Hawking radiation saturates to the nonextensive extension of the Bekenstein-Hawking entropy. Finally, we study the dependence of nonextensive parameters on the Page time.

Ankit Anand

Dinesh Kumar

Aditya Singh

Effect of a nonextensive parameter on the Page curve

We compute the entanglement entropy of Hawking radiation in a bath attached to a deformed eternal AdS black hole. This black hole is dual to the two identical strongly coupled large- <math altimg='si1.svg'><msub><mrow><mi>N</mi></mrow><mrow><mi>c</mi></mrow></msub></math> thermal field theories, where each theory is backreacted (deformed) by the presence of a uniform static distribution of heavy fundamental quarks. In our observation we find that the entanglement entropy of Hawking radiation increases in a quadratic manner for an early time and linearly for the late time. The large time expression for the entanglement entropy of Hawking radiation is used to find the Page curve and Page time. After the Page time, the entanglement entropy saturates to a constant value due to the appearance of an island. We observe that introducing deformation (backreaction) delays the appearance of island and shifts the Page curve to a later time. Subsequently, the computation of the scrambling time reveals an increase with the backreaction parameter, suggesting a longer duration for information retrieval in the presence of deformation. Moreover, our analysis of the mutual information between the radiation subsystems shows that it vanishes at a critical time which increases with the deformation before the Page time. After the Page time, the appearance of island leads to the vanishing of mutual information between black hole subsystems and gives the time difference of the order of scrambling time.

South Korea

Parul Jain

Sanjay Pant

Taiwan

Himanshu Parihar

Effect of backreaction on island, Page curve and mutual information

We investigate the combined effect of rotation and finite chemical potential in the confinement/deconfinement transition of strongly interacting matter. The holographic description consists of a five-dimensional geometry that contains a black hole (BH) in the deconfined (plasma) phase. The geometry is equipped with some cut-off that introduces an infrared energy scale. We consider two possibilities: the so-called hard wall and soft wall AdS/QCD models. The transition between the plasma and hadronic phases is represented holographically as a Hawking-Page transition between geometries with and without a black hole. The gravitational dual of the rotating plasma at finite density is given by a Reissner-Nordström (RN) charged anti-de Sitter (AdS) BH with non-zero angular momentum. This analysis provides the critical temperature of deconfinement as a function of the quark chemical potential and the plasma rotational velocity. For the case of very low temperatures, the dependence of the critical values of the chemical potential for the transition to occur at <math altimg='si1.svg'><mi>T</mi><mo stretchy='false'>&#8594;</mo><mn>0</mn></math> on the rotation is found.

Brazil

Nelson R.F. Braga

Octavio C. Junqueira

Holographic QCD phase diagram for a rotating plasma in the Hawking-Page approach

Near the doubly-magic nucleus 78Ni ( <math altimg='si1.svg'><mi>Z</mi><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>28</mn></math>, <math altimg='si2.svg'><mi>N</mi><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>50</mn></math>), there has been a decades-long debate on the existence of a long-lived isomer in 76Cu. A recent mass measurement claimed to have settled the debate, by measuring the energy of the isomer and shedding light on the structure of the nucleus. In this work, we present new, more accurate, and precise values of the half-lives of the isomeric and ground states in 76Cu. Our findings suggest that both states have very similar half-lives, in the 600&#8211;700 ms range, in disagreement with the literature values, implying that they cannot be differentiated by their decay curves. These results raise more questions than they answer, reopening the debate and showing that the structures in 76Cu are still not fully understood.

B. Olaizola

D.P. Suárez-Bustamante

G. Del Piccolo

Poland

M. Araszkiewicz

Y. Ayyad

South Africa

R.A. Bark

Z. Favier

F. Galtarossa

G. Georgiev

P.T. Greenless

R. Grzywacz

P. Ibañez

K. Johnston

P.M. Jones

A. Korgul

U. Köster

J. Kurcewicz

M. Labiche

M. Llanos-Expósito

Czechia

R.E. Mihai

E. Nácher

C. Neacsu

V.M. Nouvilas

J. Ojala

J.N. Orce

C.A.A. Page

J. Pakarinen

J. Papadakis

M. Piersa-Siłkowska

A.M. Plaza

Zs. Podolyák

W. Poklepa

F. Rotaru

M. Siciliano

J.M. Udías

R. Wadsworth

H. De Witte

D. Yates

The 76Cu conundrum remains unsolved

We propose that the quantum states of black hole responsible for the Bekenstein-Hawking entropy are given by a thin shell of Bell particles located at the region just underneath the horizon. We argue that the configuration can be stabilized by a new kind of degeneracy pressure which is suggested by a noncommutative geometry in the interior of the black hole. Black hole singularity is avoided. We utilize the work of Parikh and Wilczek <cross-ref refid='br0010' id='crf0060'>[1]</cross-ref> to include the effect of tunneling on the Bell particles. We show that partially tunneled Bell particles give the Page curve of Hawking radiation, and the entirety of information initially stored in the black hole is returned to the outside via the Hawking radiation. In view of entropic force, the location of these Bell states is naturally related to the island and the quantum extremal surface.

Chong-Sun Chu

Rong-Xin Miao

Tunneling of Bell particles, page curve and black hole information

To explore the inverse problem tied to the Page curve phenomenon and island paradigm, we investigate the geometric conditions underpinning black hole evaporation, where information is preserved and islands manifest, giving rise to the characteristic Page curve. Focusing on a broad class of static spherical symmetry black hole metrics in asymptotically Minkowski or (anti-)de Sitter spacetimes, we derive a pivotal constraint, the second derivative of the blacken factor $ f^{\prime \prime}(r_h) \lt \frac{6 \kappa A^{\prime}(r_h)}{cG_N} $ for which the island exists, and reproduce the Page curve. Moreover, starting from the quantum focusing conjecture theory, we obtain another constraint on the blacken factor for which the theory can be satisfied: $f^{\prime \prime}(r_h) \lt \frac{6 \kappa^2 r_h A^{\prime}(r_h) {\rm e}^{2\kappa r_{\star}(b)} }{cG_N f(b)}$ . In particular, by studying these two constraints, we find common properties. Specifically, we reveal that a universal criterion, manifested in the negativity of the second derivative of $ f(r) $ , i.e., $ f^{\prime \prime} (r) \lt 0 $ , in proximity to the event horizon where $ r \sim r_h+ {\cal O} (G_N) $ , ensures the emergence of Page curves and follows the quantum focusing conjecture in a manner transcending specific theoretical models. Finally, we argue that the negativity of the second derivative of the blacken factor $ f(r) $ near the event horizon strongly indicates negative heat capacity, which implies that black holes with a negative heat capacity must have islands and satisfy the quantum focusing conjecture.

Ming-Hui Yu

Xian-Hui Ge

Geometric constraints via Page curves: insights from island rule and quantum focusing conjecture * Project partially supported by the National Science Foundation of China (12275166, 12311540141)

The lifetimes of low-lying excited states below the <math altimg='si1.svg'><msup><mrow><mn>8</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> seniority isomer were directly measured using fast timing detectors in the neutron-deficient isotopes 98,100Cd. This experiment was conducted with the DEcay SPECtroscopy (DESPEC) setup at GSI, where the ions of interest were produced via a fragmentation reaction and identified using the FRagment Separator (FRS) before being implanted in the AIDA active stopper system, and the <italic>&#947;</italic> rays emitted during the de-excitation of isomeric states were detected by the LaBr <inf>3</inf> FATIMA Array. The newly deduced values for the reduced transition probabilities were compared with shell-model calculations using different interactions and effective charges. The results indicate that, while 98Cd aligns well with a seniority scheme description, in 100Cd the transition strengths among low-lying states are not fully reproduced, and the nature of these states remains an open problem within the present theoretical description. Ultimately, a key element in the description of this region, crucial for nuclear physics and astrophysics, appears to be the proton-neutron term of the nuclear effective interaction.

G. Zhang

M. Polettini

D. Mengoni

Approaching 100Sn: Structural evolution in 98,100Cd via lifetime measurements