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Jiangyang You

Publications and source records attributed to Jiangyang You.

At least 19 recordsLinked to original sources

Quantum noncommutative ABJM field theory: four- and six-point functions

Following our previous paper Quantum noncommutative ABJM theory: first steps, JHEP {\bf 1804} (2018) 070), in this article we investigate one-loop 1PI four-, and six-point functions by using the component formalism in the Landau gauge and show that they are UV finite and have well-defined $(\theta^{\mu\nu}\rightarrow 0)$ limit. Those results also hold for all one-loop functions which are UV finite by power counting. In summary, taking into account results from previous paper, JHEP {\bf 1804} (2018) 070), and this paper, we conclude that, at least at one-loop order, the NCABJM theory is free from the noncommutative UV and IR instabilities, and that in the limit $\theta^{\mu\nu}\rightarrow 0$ it flows to the ordinary ABJM theory.

hep-th

Revisiting NCQED and scattering amplitudes

Research progresses on the noncommutative gauge theories on the Moyal space are discussed in this minireview. We first present a brief overview on the development of gauge theories on Moyal space, with an emphasis on the role of Seiberg-Witten maps. Two important relations induced by reversible Seiberg-Witten maps, namely the formal equivalence of on-shell DeWitt background field effective action in general and explicit identical relation between tree level scattering amplituded in noncommutative quantum electrodynamics (NCQED), are described in some details. We then proceed to the properties of the tree level two-by-two scattering amplitudes in NCQED, including a forward scattering singularity in NCQED Compton scattering. After covering some phenomenological perspectives of NCYM based models, outlooks into the future are given at the end.

hep-th

Remarks on Compton forward scattering singularity in the NCQED

We investigate the behaviour of head-to-head high energy Compton scattering in the $\theta$-exact noncommutative (NC) quantum electrodynamics (QED) on the Moyal space (NCQED) in the amid its unresolved forward scattering singularity. We model the effect of the currently unknown resolution to this unavoidable collinear singularity by cut-offs which are functions of the control variable $s/\Lambda_{\rm NC}^2$, and find that such cut-off functions can suppress NC corrections to the inverse Compton scattering to negligible. Discussed cut-offs leave the unpolarised integral cross section of the forward region larger than the backward region all the time, making the former potentially easier to observe. Our estimations indicate that such an effect may be visible in the future collider experiments when the NC scale $\Lambda_{\rm NC}\gtrsim1$ TeV.

hep-ph

Seiberg-Witten maps and scattering amplitudes of NCQED

The connection between tree-level scattering amplitudes and the Seiberg-Witten (SW) map in the Moyal deformed U(1) noncommutataive quantum electrodynamics (NCQED) is studied. We show that in the minimal U(1) NCQED based on a reversible Seiberg-Witten (SW) map, SW map induced interactions cancel each other in all tree-level scattering amplitudes and leave them identical to the Moyal NCQED without SW map. On the other hand, the two-by-two Compton and light-by-light scattering amplitudes deviate from minimal model when irreversible SW map is used. Therefore the risibility of SW map and equivalence between NCQED before and after SW map manifest themselves as an identity between the tree-level scattering amplitudes.

hep-th

UV/IR mixing in Noncommutative SU(N) Yang-Mills theory

We show that there are one-loop IR singularities arising from UV/IR mixing in noncommutative SU(N) Yang-Mills theory defined by means of the $θ$-exact Seiberg-Witten map. This is in spite of the fact that there are no ordinary U(1) gauge fields in the theory and this is at variance with the noncommutative U(N) case, where the two-point part of the effective action involving the ordinary SU(N) fields do not suffer from those one-loop IR singularities.

hep-th

Seiberg-Witten map Invariant Scatterings

We investigate Scattering amplitudes of the reversible $\theta$-exact Seiberg-Witten (SW) map based noncommutative (NC) quantum electrodynamics, and show explicitly the SW map invariance for all tree-level NCQED $2\to2$ proceses, including M\"oller, Bhabha, Compton, pair annihilation, pair production and light-by-light $(\gamma\gamma\to\gamma\gamma)$ scatterings. We apply our NCQED results to the $\gamma\gamma\to\gamma\gamma$ and $\gamma\gamma\to\ell^+\ell^-$ exclusive processes, convoluted to the ultraperipheral lead $^{208}$Pb ion-ion collisions, recently measured by the ATLAS collaboration at LHC. We demonstrate that $\gamma\gamma\to\gamma\gamma$ is the more appropriate channel to probe NC scale $\Lambda_{\rm NC}$ while both are less efficient than some other probes.

hep-ph

Light-by-Light Scattering and Spacetime Noncommutativity

The aim of this article is to explore a potential usability of a photon-photon self-interaction from the noncommutative quantum electrodynamics (NCQED) in the case of light-by-light scattering ($γγ\toγγ$) in ultraperipheral Pb+Pb collisions, a reaction measured recently by ATLAS and planned for future experiments in hadron-hadron colliders. We compute the total cross section from both, the full one-loop standard model (SM) and the tree-level NCQED amplitudes, in the equivalent photon approximation with impact parameters, for various noncommutative scales, $\rmΛ_{NC}$, and incoming nuclear spin-energy combinations. We find that NCQED contribution to the cross section has considerable increase at diphoton invariant mass range higher than $\rmΛ_{NC}$, while the SM contribution is strongly suppressed in such region. Our results show that the current ATLAS $\rm\sqrt{s_{NN}} = 5.02$ TeV experiment can only probe $\rmΛ_{NC}<100$ GeV region. On the other hand, future hadron-hadron collider proposals could have the potential to extend to $\rmΛ_{NC}\lesssim 300$ GeV region, making the performance of $\rm Pb+Pb(γγ)\to Pb+Pbγγ$ scattering on testing space-time noncommutativity close to that of the previously proposed photon-photon mode of linear electron-positron collider.

hep-ph

Embedded electron spin decoherence as indicator of the matrix material structure

In this work the problem of characterizing matrix material structure from embedded electron spin decoherence is studied both theoretically and experimentally. Theoretical calculation using nuclear spin bath model and cluster correlation expansion method shows that the positions of decoherence time scale extremums among single crystal orientations of the matrix material coincide with those of the nearest neighbour proton dipolar couplings. This finding is confirmed by single crystal pulsed EPR experiment performed on $γ$-irradiated malonic acid (MA). Electron spin decoherence decay profile in polycrystalline matrix material is obtained from the orientation dependence as an average over sampled orientations on a Fibonacci grid. In addition, it is pointed out theoretically that a further removal of crystal ordering in the nuclear spin bath can reduce decoherence time scale from the polycrystalline value. This prediction is verified experimentally by the Hahn echo time decay scale in a new amorphous polymorph of MA, obtained for the first time by mechanical milling. Thus the embedded electron spin decoherence can be viewed as a quantitative indicator for studying structures and/or structure changes of the matrix material.

cond-mat.mtrl-sci

Inferring type and scale of noncommutativity from the PTOLEMY experiment

If neutrinos are Dirac particles and their right-handed component can be copiously produced in the early universe, then they could influence a direct observation of the cosmic neutrino background, which, most likely, will come about with the recently proposed PTOLEMY experiment. For the production mechanism of right-handed neutrinos we use a state-of-the-art version of gauge field theory deformed by the spacetime noncommutativity, to disclose by it not only the decoupling temperature for the said neutrino component, but also the otherwise hidden coupling temperature. Considering two relevant processes, the plasmon decay and the neutrino elastic scattering, we study the interplay between the structure of the noncommutativity parameter $θ^{μν}$ (type of noncommutativity) and the reheating temperature after inflation to obtain otherwise elusive upper bound on the scale of noncommutativity $Λ_{\rm NC}$. If PTOLEMY enhanced capture rate is due to spacetime noncommutativity, we verify that a nontrivial maximum upper bound on $Λ_{\rm NC}$ (a way below the Planck scale) emerges for a space-like $θ^{μν}$ and sufficiently high reheating temperature.

hep-ph

Quantum noncommutative ABJM theory: first steps

We introduce ABJM quantum field theory in the noncommutative spacetime by using the component formalism and show that it is N=6 supersymmetric. For the U(1)_κ x U(1)_{-κ} case, we compute all one-loop 1PI two and three point functions in the Landau gauge and show that they are UV finite and have well-defined commutative limits theta^{μν} -> 0, corresponding exactly to the 1PI functions of the ordinary ABJM field theory. This result also holds for all one-loop functions which are UV finite by power counting. It seems that the quantum noncommutative ABJM field theory is free from the noncommutative IR instabilities.

hep-th

UV/IR Mixing in Nonassociative Snyder phi^4 Theory

Using a quantization of the nonassociative and noncommutative Snyder phi^4 scalar field theory in a Hermitian realization, we present in this article analytical formulas for the momentum-conserving part of the one-loop two-point function of this theory in D-, 4-, and 3-dimensional Euclidean spaces, which are exact with respect to the noncommutative deformation parameter beta. We prove that these integrals are regularized by the Snyder deformation. These results indicate that the Snyder deformation does partially regularize the UV divergences of the undeformed theory, as it was proposed decades ago. Furthermore, it is observed that different nonassociative phi^4 products can generate different momentum-conserving integrals. Finally most importantly, a logarithmic infrared divergence emerges in one of these interaction terms. We then analyze sample momentum nonconserving integral qualitatively and show that it could exhibit IR divergence too. Therefore infrared divergences should exist, in general, in the Snyder phi^4 theory. We consider infrared divergences at the limit p -> 0 as UV-IR mixings induced by nonassociativity, since they are associated to the matching UV divergence in the zero-momentum limit and appear in specific types of nonassociative phi^4 products. We also discuss the extrapolation of the Snyder deformation parameter beta to negative values as well as certain general properties of one-loop quantum corrections in Snyder phi^4 theory at the zero-momentum limit.

hep-th

Nonassociative Snyder phi4 Quantum Field Theory

In this article we define and quantize a truncated form of the nonassociative and noncommutative Snyder phi^4 field theory using the functional method in momentum space. More precisely, the action is approximated by expanding up to the linear order in the Snyder deformation parameter beta, producing an effective model on commutative spacetime for the computation of the two-, four- and six-point functions. The two- and four-point functions at one loop have the same structure as at the tree level, with UV divergences faster than in the commutative theory. The same behavior appears in the six-point function, with a logarithmic UV divergence and renders the theory unrenormalizable at beta^1 order except for the special choice of free parameters s_1=-s_2. We expect effects from nonassociativity on the correlation functions at beta^1 order, but these are cancelled due to the average over permutations.

hep-th

Spacetime Deformation Effect on the Early Universe and the PTOLEMY Experiment

Using a fully-fledged formulation of gauge field theory deformed by the spacetime noncommutativity, we study its impact on relic neutrino direct detection, as proposed recently by the PTOLEMY experiment. The noncommutative background tends to influence the propagating neutrinos by providing them with a tree-level vector-like coupling to photons, enabling thus otherwise right-handed (RH) neutrinos to be thermally produced in the early universe. Such a new component in the universe's background radiation has been switched today to the almost fully active sea of non-relativistic neutrinos, exerting consequently some impact on the capture on tritium at PTOLEMY. The peculiarities of our nonperturbative approach tend to reflect in the cosmology as well, upon the appearances of the coupling temperature, above which RH neutrinos stay permanently decoupled from thermal environment. This entails the maximal scale of noncommutativity as well, being of order of $10^{-4} M_{Pl}$, above which there is no impact whatsoever on the capture rates at PTOLEMY. The latter represents an exceptional upper bound on the scale of noncommutativity coming from phenomenology.

hep-ph

Equivalence and/or quantum duality of the non/supersymmetric noncommutative field theories related by the theta-exact Seiberg-Witten map

In this article we expound a discovery of the quantum equivalence/duality of U(N) noncommutative quantum field theories (NC QFT) related by the theta-exact Seiberg-Witten (SW) maps and at all orders in the perturbation theory with respect to the coupling constant. We show that this proof holds for Super Yang-Mills (SYM) theories with N=0,1,2,4$ supersymmetry. In short, Seiberg-Witten map does commute with the quantization of the U(N) NCQFT independently, with or without supersymmetry.

hep-th

Quantum duality under the theta-exact Seiberg-Witten map

We show that in the perturbative regime defined by the coupling constant, the theta-exact Seiberg-Witten map applied to noncommutative U(N) Yang-Mills --with or without Supersymmetry-- gives an ordinary gauge theory which is, at the quantum level, dual to the former. We do so by using the on-shell DeWitt effective action and dimensional regularization. We explicitly compute the one-loop two-point function contribution to the on-shell DeWitt effective action of the ordinary U(1) theory furnished by the theta-exact Seiberg-Witten map. We find that the non-local UV divergences found in the propagator in the Feynman gauge all but disappear, so that they are not physically relevant. We also show that the quadratic noncommutative IR divergences are gauge-fixing independent and go away in the Supersymmetric version of the U(1) theory.

hep-th

Equivalence of quantum field theories related by the theta-exact Seiberg-Witten map

The equivalence of the noncommutative U(N) quantum field theories related by the theta-exact Seiberg-Witten maps is in this letter proven to all orders in the perturbation theory with respect to the coupling constant. We show that this duality holds for Super Yang-Mills theories with N=0,1,2,4 supersymmetry. A direct check of this equivalence relation is performed by computing the one-loop quantum corrections to the quadratic part of the effective action in the noncommutative U(1) gauge theory with N=0,1,2,4 supersymmetry.

hep-th

Super Yang-Mills and theta-exact Seiberg-Witten map: Absence of quadratic noncommutative IR divergences

We compute the one-loop 1PI contributions to all the propagators of the noncommutative N=1, 2, 4 super Yang-Mills (SYM) U(1) theories defined by the means of the theta-exact Seiberg-Witten (SW) map in the Wess-Zumino gauge. Then we extract the UV divergent contributions and the noncommutative IR divergences. We show that all the quadratic noncommutative IR divergences add up to zero in each propagator.

hep-th

Photon polarization tensor on deformed spacetime: A four-photon-tadpole contribution

In this contribution to the Proceedings of the Corfu Summer Institute 2015 we present our study on photon self-interaction in the deformed U(1) gauge field theory defined via Seiberg-Witten map. We derive the theta-exact expressions for the four photon self-coupling in this theory with a large number of gauge symmetry inspired freedom parameters included. The physical effect of four photon self-coupling is accessed by its contribution to photon polarization tensor via 1-loop four-photon-tadpole-diagram. The four-photon tadpole diagram consists the same tensorial structures as the photon self-interacting bubble diagram we studied before, with however only quadratically IR divergent coefficients. We show that there exists a unique combination of gauge symmetry inspired freedoms which induces full quadratic IR divergence cancellation for arbitrary noncommutative parameter theta once the photon self-interacting bubble and tadpole diagrams are summed over.

hep-th