The Experts below are selected from a list of 18072 Experts worldwide ranked by ideXlab platform

Junjie Rao - One of the best experts on this subject based on the ideXlab platform.

  • all loop mondrian reduction of 4 particle amplituhedron at Positive Infinity
    Nuclear Physics, 2020
    Co-Authors: Junjie Rao
    Abstract:

    Abstract This article introduces a systematic framework to understand (not to derive yet) the all-loop 4-particle amplituhedron in planar N = 4 SYM, utilizing both positivity and the Mondrian diagrammatics. Its key idea is the simplest one so far: we can decouple one or more sets of loop variables ( x , y , z , w ) from the rest by just setting these variables to either zero or Infinity so that their relevant positivity conditions are trivialized, then the all-loop consistency requires that we get lower loop amplituhedra as “residues”. These decoupling relations connect higher loop DCI integrals with the lower ones, enabling us to identify their coefficients starting from the 3-loop case. And surprisingly, the delicate mechanism of this process is the simple Mondrian rule D = X + Y , which forces those visually non-Mondrian DCI integrals to have the correct coefficients such that the amplituhedron can exactly reduce to the lower loop one. Examples cover all DCI integrals at L = 3 , 4 , 5 , 6 , especially, the subtle 6-loop coefficients +2 and 0 are neatly explained in this way.

  • triangulation free trivialization of 2 loop mhv amplituhedron
    Journal of High Energy Physics, 2020
    Co-Authors: Ryota Kojima, Junjie Rao
    Abstract:

    This article introduces a new approach to implement positivity for the 2-loop n-particle MHV amplituhedron, circumventing the conventional triangulation with respect to Positive variables of each cell carved out by the sign flips. This approach is universal for all linear Positive conditions and hence free of case-by-case triangulation, as an application of the trick of Positive Infinity first introduced in [6] for the multi-loop 4-particle amplituhedron. Moreover, the proof of 2-loop n-particle MHV amplituhedron in [4] is revised, and we explain the nontriviality and difficulty of using conventional triangulation while the results have a simple universal pattern. A further example is presented to tentatively explore its generalization towards handling multiple Positive conditions at 3-loop and higher.

Wei S. - One of the best experts on this subject based on the ideXlab platform.

  • Microstructure of charged AdS black hole via P-V criticality
    'American Physical Society (APS)', 2020
    Co-Authors: Dehyadegari A., Sheykhi A., Wei S.
    Abstract:

    We suggest a new thermodynamic curvature, constructed via adiabatic compressibility, for examining the internal microstructure of charged black holes in an anti-de Sitter (AdS) background. We analyze the microscopic properties of small-large phase transition of black holes with pressure and volume as the fluctuation variables. We observe that strong repulsive interactions dominate among the micro-structures of near extremal small black holes, and the thermodynamic curvature diverges to Positive Infinity for the extremal black holes. At the critical point, however, thermodynamic curvature diverges to negative Infinity

Wei Shao-wen - One of the best experts on this subject based on the ideXlab platform.

  • Microstructure of charged AdS black hole via $P-V$ criticality
    2020
    Co-Authors: Dehyadegari Amin, Sheykhi Ahmad, Wei Shao-wen
    Abstract:

    We suggest a new thermodynamic curvature, constructed via adiabatic compressibility, for examining the internal microstructure of charged black holes in an anti-de Sitter (AdS) background. We analyze the microscopic properties of small-large phase transition of black holes with pressure and volume as the fluctuation variables. We observe that strong repulsive interactions dominate among the micro-structures of near extremal small black holes, and the thermodynamic curvature diverges to Positive Infinity for the extremal black holes. At the critical point, however, thermodynamic curvature diverges to negative Infinity.Comment: 7 pages,4 figure

Perry Ping Shum - One of the best experts on this subject based on the ideXlab platform.

  • Instantaneous Microwave Frequency Measurement Using a Photonic Microwave Filter With an Infinite Impulse Response
    IEEE Photonics Technology Letters, 2010
    Co-Authors: Junqiang Zhou, Singh Aditya, Perry Ping Shum
    Abstract:

    A photonic technique for instantaneous microwave frequency measurement is proposed. In the proposed technique, a photonic microwave filter having a monotonic frequency response with the magnitude varying from Positive Infinity to negative Infinity on a log scale, is constructed by cascading two photonic microwave filters with one having an infinite impulse response and the other having a finite impulse response. For a single-frequency microwave signal with a normalized magnitude, a unique relationship between the output response and the input frequency is established. Since the response extends from Positive to negative Infinity, for a given measurement range, a significantly increased measurement resolution is achieved. The proposed technique is verified by an experiment.

E De Prunele - One of the best experts on this subject based on the ideXlab platform.

  • two electron atoms o 4 2 operator replacements and large order perturbation theory with respect to the replaced kinetic energy operator
    Physical Review A, 1994
    Co-Authors: Igor Ivanov, E De Prunele
    Abstract:

    The Schr\"odinger equation for two-electron atoms is transformed into an alternative equation depending on a free dimensionless parameter \ensuremath{\beta}, according to the method of o(4,2) operator replacements. These operator replacements are well defined except for the case where both the orbital and spin momenta are zero, i.e., except for singlet S states. When \ensuremath{\beta} goes to Positive Infinity, the solutions of this present equation should correspond to the solutions of the Schr\"odinger equation. When \ensuremath{\beta} goes to negative Infinity, the present equation becomes exactly solvable. These exact solutions are the zero-order solutions for a Rayleigh-Schr\"odinger perturbative expansion where the perturbation is the nondiagonal part of the replaced kinetic-energy operator. An essential property of this method is that the perturbative operator is bounded, and therefore the convergence radius of the series is nonzero. The method is purely nonvariational. A numerical application for the triplet S even-parity ground-state helium atom is performed.