12,577 research outputs found

    Top Yukawa coupling measurement with indefinite CP Higgs in e+ettˉΦe^+e^-\to t\bar{t}\Phi

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    We consider the issue of the top quark Yukawa coupling measurement in a model in dependent and general case with the inclusion of CP-violation in the coupling. Arguably the best process to study this coupling is the associa ted production of Higgs boson along with a ttˉt\bar t pair in a machine like the International Linear Collider (ILC). While detailed analyses of the sensitivity of the measurement assuming a Standard Model (SM) - like coupling are available in the context of ILC, conclude that th e coupling could be pinned down at about 10\% level with modest luminosity, our investigations show that the scenario could be different in case of a more general coupling. The modified Lorentz structure resulting in a changed functional dependence of the cross section on the couplin g, along with the difference in the cross section itself leads to considerable deviation in the sensitivity. Our studies with an ILC of center of mass energies of 500 GeV, 800 GeV and 1000 GeV show that moderate CP-mixing in the Higgs sector could change the sensitivity to about 20\ %, while it could be worsened to 75\% in cases which could accommodate more dramatic changes in the coupling. While detailed considerations of the decay distributions point to a need for a relook at the analysis strategy followed for the case of SM such as for a model independent analysis of the top quark Yukawa coupling measurement. This study strongly suggests that, a joint analysis of the CP properties and the Yukawa coupling measurement would be the way forward at the ILC and that caution must be excercised in the measurem ent of the Yukawa couplings and the conclusions drawn from it.Comment: 18 pages, 7 figures, uses revte

    Measurement Uncertainty in Vibration Calibration in Frequency Range of 5 Hz to 10 kHz

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    The paper evaluates the measurement uncertainty in realizing the secondary vibration standard at CSIR-National Physical Laboratory, India, and presents a comparison of the measurement uncertainty of secondary standard with that of primary vibration standard. The relative expanded measurement uncertainty of 0.80% to 2.2% in frequency range of 5 Hz to 10 kHz is evaluated. The measurement uncertainty so calculated is verified by comparison with the results from primary vibration calibration standard of CSIR-National Physical Laboratory, New Delhi, and SPEKTRA Schwingungstechnik und Akustik GmbH Dresden, Germany primary calibrations. The study recommends calibrating the back-to-back accelerometer with minimal uncertainty by using a primary calibrated single-ended accelerometer mounted on the top of the back-to-back transducer.The paper serves a guiding document to the calibration laboratories, industries and other stake holders in India to understand the concept of traceability in vibration measurements and formulation of uncertainty budget as per the international standard

    Private Outsourcing of Polynomial Evaluation and Matrix Multiplication using Multilinear Maps

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    {\em Verifiable computation} (VC) allows a computationally weak client to outsource the evaluation of a function on many inputs to a powerful but untrusted server. The client invests a large amount of off-line computation and gives an encoding of its function to the server. The server returns both an evaluation of the function on the client's input and a proof such that the client can verify the evaluation using substantially less effort than doing the evaluation on its own. We consider how to privately outsource computations using {\em privacy preserving} VC schemes whose executions reveal no information on the client's input or function to the server. We construct VC schemes with {\em input privacy} for univariate polynomial evaluation and matrix multiplication and then extend them such that the {\em function privacy} is also achieved. Our tool is the recently developed {mutilinear maps}. The proposed VC schemes can be used in outsourcing {private information retrieval (PIR)}.Comment: 23 pages, A preliminary version appears in the 12th International Conference on Cryptology and Network Security (CANS 2013

    Universal features of Thermopower in High Tc systems and Quantum Criticality

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    In high Tc superconductors a wide ranging connection between the doping dependence of the transition temperature Tc and the room temperature thermopower Q has been observed. A "universal correlation" between these two quantities exists with the thermopower vanishing at optimum doping as noted by OCTHH (Obertelli, Cooper, Tallon, Honma and Hor). In this work we provide an interpretation of this OCTHH universality in terms of a possible underlying quantum critical point (QCP) at Tc. Central to our viewpoint is the recently noted Kelvin formula relating the thermopower to the density derivative of the entropy. Perspective on this formula is gained through a model calculation of the various Kubo formulas in an exactly solved 1-dimensional model with various limiting procedures of wave vector and frequency.Comment: 12 pages, 8 figure

    Quantum Lightning Never Strikes the Same State Twice

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    Public key quantum money can be seen as a version of the quantum no-cloning theorem that holds even when the quantum states can be verified by the adversary. In this work, investigate quantum lightning, a formalization of "collision-free quantum money" defined by Lutomirski et al. [ICS'10], where no-cloning holds even when the adversary herself generates the quantum state to be cloned. We then study quantum money and quantum lightning, showing the following results: - We demonstrate the usefulness of quantum lightning by showing several potential applications, such as generating random strings with a proof of entropy, to completely decentralized cryptocurrency without a block-chain, where transactions is instant and local. - We give win-win results for quantum money/lightning, showing that either signatures/hash functions/commitment schemes meet very strong recently proposed notions of security, or they yield quantum money or lightning. - We construct quantum lightning under the assumed multi-collision resistance of random degree-2 systems of polynomials. - We show that instantiating the quantum money scheme of Aaronson and Christiano [STOC'12] with indistinguishability obfuscation that is secure against quantum computers yields a secure quantum money schem

    Electronic structure of Pr0.67_{0.67}Ca0.33_{0.33}MnO3_3 near the Fermi level studied by ultraviolet photoelectron and x-ray absorption spectroscopy

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    We have investigated the temperature-dependent changes in the near-EEF_F occupied and unoccupied states of Pr0.67_{0.67}Ca0.33_{0.33}MnO3_3 which shows the presence of ferromagnetic and antiferromagnetic phases. The temperature-dependent changes in the charge and orbital degrees of freedom and associated changes in the Mn 3dd - O 2pp hybridization result in varied O 2pp contributions to the valence band. A quantitative estimate of the charge transfer energy (EECT_{CT}) shows a larger value compared to the earlier reported estimates. The charge localization causing the large EECT_{CT} is discussed in terms of different models including the electronic phase separation.Comment: 19 pages, 7 figures, To be published in Phy. Rev.

    A Composite Chiral Pair of Rotational Bands in the odd-A Nucleus 135Nd

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    High-spin states in 135Nd were populated with the 110Pd(30Si,5n)135Nd reaction at a 30Si bombarding energy of 133 MeV. Two Delta(I)=1 bands with close excitation energies and the same parity were observed. These bands are directly linked by Delta(I)=1 and Delta(I)=2 transitions. The chiral nature of these two bands is confirmed by comparison with three-dimensional tilted axis cranking calculations. This is the first observation of a three-quasiparticle chiral structure and established the primarily geometric nature of this phenomenon.Comment: 10 pages, 5 figures (1 in color), 1 table, submitted to Physics Review Letters, written in REVTEX4 forma
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