In this paper, we present an algorithm to construct the q  T  distribution at NLO accuracy to arbitrary power precision, including the assembly of suitable zero-bin subtrahends, in a mathematically well-defined way for a generic choice of rapidity-divergence regularisation prescription. In its derivation, we divide the phase space into two sectors, the interior of the integration domain as well as the integration boundary, which we include here for the first time. To demonstrate the applicability and usefulness of our algorithm, we calculate the N2LP corrections for Higgs hadroproduction for the first time. We observe that our approximate N2LP-accurate q  T  spectra replicate the asymptotic behaviour of the full QCD calculation to a much better degree than the previously available results, both within the q  T  → 0 limit and in the large-q  T  domain for all the involved partonic processes. While playing a minor role at larger transverse momenta, we show that the newly incorporated boundary contribution plays a vital role in the q  T  → 0 limit, where any subleading power accuracy would be lost without them. In particular, our N2LP-accurate q  T  expansion can approximate the exact q  T  distribution up to q  T  ≈ 30 GeV at the percent level for rapidities |Y  H  | ≲ 3.

Italy

Giancarlo Ferrera

Wan-Li Ju

United Kingdom

Marek Schönherr

Zero-bin subtraction and the q T spectrum beyond leading power

Abstract The open N = 2 string theory is defined on the 4D space-time with the split signature (+, +, −, −). The string field theory action of the open N = 2 string theory is described by the 4D Wess–Zumino–Witten (WZW$_{4}$) model. The equation of motion of the WZW$_{4}$ model is the Yang equation, which is equivalent to the anti-self-dual Yang–Mills equation. In this paper, we study soliton-type classical solutions of the WZW$_{4}$ model in the split signature by calculating the action density of the WZW$_{4}$ model. We find that the action density of the one-soliton solutions is localized on a 3D hyperplane. This shows that there would be codimension-one-solitonic objects, or equivalently some kind of three-branes in the open N = 2 string theory. We also prove that, in the asymptotic region of the space-time, the action density of the n-soliton solutions is a “non-linear superposition” of n one-solitons. This suggests the existence of n intersecting three-branes in the N = 2 strings. Finally we make a reduction to a (1 + 2)D real space-time to calculate the energy densities of the soliton solutions. We can successfully evaluate the energy distribution for the two-soliton solutions and find that there is no singularity in the interacting region. This implies the existence of smooth intersecting codimension-one branes in the whole region. Soliton solutions in the Euclidean signature are also discussed.

Japan

Masashi Hamanaka

Shan-Chi Huang

Hiroaki Kanno

Solitons in open = 2 String Theory Kahler-Chen-Simons theory A tour through N=2 strings On soliton solutions of the anti-self-dual Yang-Mills equations from the perspective of integrable systems Soliton solutions in an integrable chiral model in 2+1 dimensions On the space-time monopole equation A review on tachyon condensation in open string field theories Soliton equations as dynamical systems on infinite dimensional Grassmann manifold

The Ryu-Takayanagi (RT) formula plays a large role in the current theory of gauge-gravity duality and emergent geometry phenomena. The recent reinterpretation of this formula in terms of a set of “bit threads” is an interesting effort in understanding holography. In this study, we investigate a quantum generalization of the “bit threads” based on a tensor network, with particular focus on the multi-scale entanglement renormalization ansatz (MERA). We demonstrate that, in the large c limit, isometries of the MERA can be regarded as “sources” (or “sinks”) of the information flow, which extensively modifies the original picture of bit threads by introducing a new variable ρ: density of the isometries. In this modified picture of information flow, the isometries can be viewed as generators of the flow. The strong subadditivity and related properties of the entanglement entropy are also obtained in this new picture. The large c limit implies that classical gravity can emerge from the information flow.
				

China

Chong-Bin Chen

Fu-Wen Shu

Meng-He Wu

Quantum bit threads of MERA tensor network in large c limit Supported in part by the National Natural Science Foundation of China (11975116, 11665016, 11563006), and Jiangxi Science Foundation for Distinguished Young Scientists (20192BCB23007)

The entanglement of purification (EoP), which measures the classical correlations and entanglement of a given mixed state, has been conjectured to be dual to the area of the minimal cross section of the entanglement wedge in holography. Using the surface-state correspondence, we propose a “bit thread” formulation of the EoP. With this formulation, proofs of some known properties of the EoP are performed. Moreover, we show that the quantum advantage of dense code (QAoDC), which reflects the increase in the rate of classical information transmission through quantum channel due to entanglement, also admits a flow interpretation. In this picture, we can prove the monogamy relation of QAoDC with the EoP for tripartite states. We also derive a new lower bound for S(AB) in terms of QAoDC, which is tighter than the one given by the Araki-Lieb inequality.

Dong-Hui Du

United States

Bit threads and holographic entanglement of purification

A concept of measuring the quantum distance between two different quantum states that is called quantum information metric has been presented. The holographic principle (anti–de Sitter/conformal field theory) suggests that the quantum information metric <math><msub><mi>G</mi><mrow><mi>λ</mi><mi>λ</mi></mrow></msub></math> between perturbed state and unperturbed state in field theory has a dual description in the classical gravity. In this work we calculate the quantum information metric of a theory that is dual to a conical defect geometry and we show that it is <math><mi>n</mi></math> times the one of its covering space. We also give a holographic check for our result in the gravity side. Meanwhile, it was argued that <math><msub><mi>G</mi><mrow><mi>λ</mi><mi>λ</mi></mrow></msub></math> is dual to a codimension-one surface in spacetime and satisfies <math><msub><mi>G</mi><mrow><mi>λ</mi><mi>λ</mi></mrow></msub><mo>=</mo><msub><mi>n</mi><mi>d</mi></msub><mo>·</mo><mi>Vol</mi><mo>(</mo><msub><mi>Σ</mi><mrow><mi>max</mi></mrow></msub><mo>)</mo><mo>/</mo><msup><mi>L</mi><mi>d</mi></msup></math>. We show that the coefficient <math><msub><mi>n</mi><mi>d</mi></msub></math> for conical defect should be rescaled by <math><msup><mi>n</mi><mn>2</mn></msup></math> from the one for anti–de Sitter space. A limit case of conical defect—the massless Banados-Teitelboim-Zannelli (BTZ) black hole—is also considered. We show that the quantum information metric of a massless BTZ black hole disagrees with the one obtained by taking the vanishing temperature limit in BTZ black hole. This provides a new arena in differentiating the different phases between BTZ spacetime and its massless cousin.

Wen-Cong Gan

Bo Xiong

Quantum information metric of conical defect

LHCb has reported hints of lepton-flavor universality violation in the rare decays B → K (*) ℓ + ℓ −, both in high- and low-q 2 bins. Although the high-q 2 hint may be explained by new short-ranged interactions, the low-q 2 one cannot. We thus explore the possibility that the latter is explained by a new light resonance. We find that LHCb’s central value of   <math> <msub> <mi>R</mi> <msup> <mi>K</mi> <mo>*</mo> </msup> </msub> </math>  $$ {R}_{K^{*}} $$  in the low-q 2 bin is achievable in a restricted parameter space of new-physics scenarios in which the new, light resonance decays preferentially to electrons and has a mass within approximately 10 MeV of the di-muon threshold. Interestingly, such an explanation can have a kinematic origin and does not require a source of lepton-flavor universality violation. A model-independent prediction is a narrow peak in the differential B → K * e + e − rate close to the di-muon threshold. If such a peak is observed, other observables, such as the differential B → Ke + e − rate and R  K , may be employed to distinguish between models. However, if a low-mass resonance is not observed and the low-q 2 anomaly increases in significance, then the case for an experimental origin of the lepton-flavor universality violating anomalies would be strengthened. To further explore this, we also point out that, in analogy to J/ψ decays, e + e − and μ + μ − decays of ϕ mesons can be used as a cross check of lepton-flavor universality by LHCb with 5 fb−1 of integrated luminosity.

Wolfgang Altmannshofer

Switzerland

Michael Baker

Stefania Gori

Roni Harnik

Canada

CERN

Maxim Pospelov

Emmanuel Stamou

Andrea Thamm

Light resonances and the low-q 2 bin of   <math> <msub> <mi>R</mi> <msup> <mi>K</mi> <mo>*</mo> </msup> </msub> </math>  $$ {R}_{K^{*}} $$

In the present paper, the exact solutions of spherically symmetrical Einstein field equations describing wormholes supported by phantom energy that violates the null energy condition from Shan–Chen background fluid are obtained. We have considered the important case of the model parameter ψ≈1 , which corresponds to the “saturation effect”, and this regime corresponds to an effective form of “asymptotic freedom” for the fluids, but occurring at cosmological rather than subnuclear scales. Then we investigate the allowed range for the values of the model parameters g and ω when the spacetime metrics describe wormholes and discuss the possible singularities of the solutions, finding that the obtained spacetimes are geodesically complete. Furthermore, we construct two traversable wormholes through matching our obtained interior solutions to the exterior Schwarzschild solutions and analyze the traversablities of the wormholes. Finally, we consider the case of anisotropic pressure and discover that the transverse pressure also crosses the phantom divide -1 with the growth of the wormhole dimension, and it tends to be the same as the radial pressure with the growth of the wormhole radius.

Deng Wang

Xin-He Meng

Wormholes supported by phantom energy from Shan–Chen cosmological fluids

We develop a new halo-independent strategy for analyzing emerging DM hints, utilizing the method of extended maximum likelihood. This approach does not require the binning of events, making it uniquely suited to the analysis of emerging DM direct detection hints. It determines a preferred envelope, at a given confidence level, for the DM velocity integral which best fits the data using all available information and can be used even in the case of a single anomalous scattering event. All of the halo-independent information from a direct detection result may then be presented in a single plot, allowing simple comparisons between multiple experiments. This results in the halo-independent analogue of the usual mass and cross-section plots found in typical direct detection analyses, where limit curves may be compared with best-fit regions in halo-space. The method is straightforward to implement, using already-established techniques, and its utility is demonstrated through the first unbinned halo-independent comparison of the three anomalous events observed in the CDMS-Si detector with recent limits from the LUX experiment.

Patrick J. Fox

Yonatan Kahn

Matthew McCullough

Taking Halo-independent dark matter methods out of the bin

None Supervisory Editors of Nuclear Physics B

Editorial note on “Lepton-flavor violation and (g−2)μ in the μν SSM” by Hai-Bin Zhang, Tai-Fu Feng, Shu-Min Zhao and Tie-Jun Gao [Nucl. Phys. B 873 (2) (2013) 300–324]