Construction of C operator for a PT symmetric model
We obtain closed form expression of the C(x,y) operator for the PT symmetric Scarf I potential. It is also shown that the eigenfunctions are complete.
quant-ph↗
arXiv subjects
P. Roy
Publications and source records attributed to P. Roy.
Higher order intertwining approach to quasinormal modes
Using higher order intertwining operators we obtain new exactly solvable potentials admitting quasinormal mode (QNMs) solutions of the Klein-Gordon equation. It is also shown that different potentials exhibiting QNMs can be related through nonlinear supersymmetry.
gr-qc↗
Shape invariance approach to exact solutions of the Klein-Gordon equation
Using the shape invariance property we obtain exact solutions of the (1+1)dimensional Klein-Gordon equation for certain types of scalar and vector potentials. We also discuss the possibility of obtaining real energy spectrum with non-Hermitian interaction within this framework.
quant-ph↗
Coherent states of non-Hermitian quantum systems
We use the Gazeau-Klauder formalism to construct coherent states of non-Hermitian quantum systems. In particular we use this formalism to construct coherent state of a PT symmetric system. We also discuss construction of coherent states following Klauder's minimal prescription.
quant-ph↗
$(1+1)$ dimensional Dirac equation with non Hermitian interaction
We study $(1+1)$ dimensional Dirac equation with non Hermitian interactions, but real energies. In particular, we analyze the pseudoscalar and scalar interactions in detail, illustrating our observations with some examples. We also show that the relevant hidden symmetry of the Dirac equation with such an interaction is pseudo supersymmetry.
quant-ph↗
$\cal{PT}$ symmetric models with nonlinear pseudo supersymmetry
By applying the higher order Darboux algorithm to an exactly solvable non Hermitian ${\cal{PT}}$ symmetric potential, we obtain a hierarchy of new exactly solvable non Hermitian ${\cal{PT}}$ symmetric potentials with real spectra. It is shown that the symmetry underlying the potentials so generated and the original one is {\it nonlinear pseudo supersymmetry}. We also show that this formalism can be used to generate a larger class of new solvable potentials when applied to non Hermitian systems.
quant-ph↗
Working Group Report: Neutrino and Astroparticle Physics
This is the report of neutrino and astroparticle physics working group at WHEPP-8. We present the discussions carried out during the workshop on selected topics in the above fields and also indicate progress made subsequently. The neutrino physics subgroup studied the possibilites of constraining neutrino masses, mixing and CPT violation in lepton sector from future experiments. Neutrino mass models in the context of abelian horizontal symmetries, warped extra dimensions and in presence of triplet Higgs were studied. Effect of threshold corrections on radiative magnification of mixing angles was investigated. The astroparticle physics subgroup focused on how various particle physics inputs affect the CMBR fluctuation spectrum, and on brane cosmology. This report also contains an introduction on how to use the publicly available code CMBFAST to calculate the CMBR fluctuations.
hep-ph↗
Investigation of top mass measurements with the ATLAS detector at LHC
Several methods for the determination of the mass of the top quark with the ATLAS detector at the LHC are presented. All dominant decay channels of the top quark can be explored. The measurements are in most cases dominated by systematic uncertainties. New methods have been developed to control those related to the detector. The results indicate that a total error on the top mass at the level of 1 GeV should be achievable.
hep-ex↗
An An exactly solvable PT symmetric potential from the Natanzon class
The ${\cal PT}$ symmetric version of the generalised Ginocchio potential, a member of the general exactly solvable Natanzon potential class is analysed and its properties are compared with those of ${\cal PT}$ symmetric potentials from the more restricted shape-invariant class. It is found that the ${\cal PT}$ symmetric generalised Ginocchio potential has a number of properties in common with the latter potentials: it can be generated by an imaginary coordinate shift $x\to x+{\rm i}ε$; its states are characterised by the quasi-parity quantum number; the spontaneous breakdown of ${\cal PT}$ symmetry occurs at the same time for all the energy levels; and it has two supersymmetric partners which cease to be ${\cal PT}$ symmetric when the ${\cal PT}$ symmetry of the original potential is spontaneously broken.
quant-ph↗
An exactly solvable PT symmetric potential from the Natanzon class
The ${\cal PT}$ symmetric version of the generalised Ginocchio potential, a member of the general exactly solvable Natanzon potential class is analysed and its properties are compared with those of ${\cal PT}$ symmetric potentials from the more restricted shape-invariant class. It is found that the ${\cal PT}$ symmetric generalised Ginocchio potential has a number of properties in common with the latter potentials: it can be generated by an imaginary coordinate shift $x\to x+{\rm i}ε$; its states are characterised by the quasi-parity quantum number; the spontaneous breakdown of ${\cal PT}$ symmetry occurs at the same time for all the energy levels; and it has two supersymmetric partners which cease to be ${\cal PT}$ symmetric when the ${\cal PT}$ symmetry of the original potential is spontaneously broken.
quant-ph↗
Measurement of the Crab Flux Above 60 GeV with the CELESTE Cherenkov Telescope
We have converted the former solar electrical plant THEMIS (French Pyrenees) into an atmospheric Cherenkov detector called CELESTE, which records gamma rays above 30 GeV (7E24 Hz). Here we present the first sub-100 GeV detection by a ground based telescope of a gamma ray source, the Crab nebula, in the energy region between satellite measurements and imaging atmospheric Cherenkov telescopes. At our analysis threshold energy of 60 +/- 20 GeV we measure a gamma ray rate of 6.1 +/- 0.8 per minute. Allowing for 30% systematic uncertainties and a 30% error on the energy scale yields an integral gamma ray flux of I(E>60 GeV) = 6.2^{+5.3}_{-2.3} E-6 photons m^-2 s^-1. The analysis methods used to obtain the gamma ray signal from the raw data are detailed. In addition, we determine the upper limit for pulsed emission to be <12% of the Crab flux at the 99% confidence level, in the same energy range. Our result indicates that if the power law observed by EGRET is attenuated by a cutoff of form e^{-E/E_0} then E_0 < 26 GeV. This is the lowest energy probed by a Cherenkov detector and leaves only a narrow range unexplored beyond the energy range studied by EGRET.
astro-ph↗
Optical conductivity of the nonsuperconducting cuprate La(8-x)Sr(x)Cu(8)O(20)
La(8-x)Sr(x)Cu(8)O(20) is a non-superconducting cuprate, which exhibits a doubling of the elementary cell along the c axis. Its optical conductivity sigma (omega) has been first measured here, down to 20 K, in two single crystals with x = 1.56 and x = 2.24. Along c, sigma (omega) shows, in both samples, bands due to strongly bound charges, thus confirming that the cell doubling is due to charge ordering. In the ab plane, in addition to the Drude term one observes an infrared peak at 0.1 eV and a midinfrared band at 0.7 eV. The 0.1 eV peak hardens considerably below 200 K, in correspondence of an anomalous increase in the sample dc resistivity, in agreement with its polaronic origin. This study allows one to establish relevant similarities and differences with respect to the spectrum of the ab plane of the superconducting cuprates.
cond-mat.supr-con↗
Exact solutions of effective mass Schroedinger equations
We outline a general method of obtaining exact solutions of Schroedinger equations with a position dependent effective mass. Exact solutions of several potentials including shape invariant potentials have also been obtained.
quant-ph↗
Supersymmetric lepton flavour violation in a linear collider: the role of charginos
The occurrence of a significant amount of supersymmetric lepton flavour violation at laboratory energies, through $\tildeν_μ- \tildeν_τ$ mixing, has become a realistic possibility in the wake of the super-Kamiokande atmospheric neutrino result. This effect can be observed in an e+e- linear collider with the distinct final state tau+mu+ jets+E_T. We show that the pair production of charginos can make an important contribution to this process and has to be taken into account in addition to that of sneutrinos or charged sleptons. Some case studies are presented with CM energies of 500 and 800 GeV and integrated luminosities of 50, 500 and 1000 fb-1.
hep-ph↗
A New Class of PT-symmetric Hamiltonians with Real Spectra
We investigate complex PT-symmetric potentials, associated with quasi-exactly solvable non-hermitian models involving polynomials and a class of rational functions. We also look for special solutions of intertwining relations of SUSY Quantum Mechanics providing a partnership between a real and a complex PT-symmetric potential of the kind mentioned above. We investigate conditions sufficient to ensure the reality of the full spectrum or, for the quasi-exactly solvable systems, the reality of the energy of the finite number of levels.
quant-ph↗
Far-infrared reflectivity of Bi_2Sr_2CuO_6: the "anomalous Drude" model and optical pseudogap revisited
An optical "pseudogap" is usually assumed to open at low T in the "anomalous Drude" absorption, which models the optical conductivity sigma(omega) (proportional to omega-1) of HCTS by a linewidth Gamma (on the order of 1000 cm-1) varying with omega. In the sigma(omega) of BSCO, measured down to 10 cm-1, we have resolved instead: i) a normal Drude term with Gamma=35 cm-1 at 30 K, in very good agreement with transport data; ii) a strong band peaked in the far infrared (FIR), likely due to bound charges, whose tail exhibits the omega-1 dependence. As the FIR peak softens for decreasing T, it opens a pseudogap-like depression in sigma(omega) accordingly to ordinary sum rules.
cond-mat.supr-con↗
Phase properties of a new nonlinear coherent state
We study phase properties of a displacement operator type nonlinear coherent state. In particular we evaluate the Pegg-Barnett phase distribution and compare it with phase distributions associated with the Husimi Q function and the Wigner function. We also study number- phase squeezing of this state.
quant-ph↗
A Lie algebraic approach to complex quasi exactly solvable potentials with real spectrum
We use a Lie algebraic technique to construct complex quasi exactly solvable potentials with real spectrum. In particular we obtain exact solutions of a complex sextic oscillator potential and also a complex potential belonging to the Morse family.
quant-ph↗