14,066 research outputs found

    A Hardy's Uncertainty Principle Lemma in Weak Commutation Relations of Heisenberg-Lie Algebra

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    In this article we consider linear operators satisfying a generalized commutation relation of a type of the Heisenberg-Lie algebra. It is proven that a generalized inequality of the Hardy's uncertainty principle lemma follows. Its applications to time operators and abstract Dirac operators are also investigated

    Field evolution of the magnetic structures in Er2_2Ti2_2O7_7 through the critical point

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    We have measured neutron diffraction patterns in a single crystal sample of the pyrochlore compound Er2_2Ti2_2O7_7 in the antiferromagnetic phase (T=0.3\,K), as a function of the magnetic field, up to 6\,T, applied along the [110] direction. We determine all the characteristics of the magnetic structure throughout the quantum critical point at HcH_c=2\,T. As a main result, all Er moments align along the field at HcH_c and their values reach a minimum. Using a four-sublattice self-consistent calculation, we show that the evolution of the magnetic structure and the value of the critical field are rather well reproduced using the same anisotropic exchange tensor as that accounting for the local paramagnetic susceptibility. In contrast, an isotropic exchange tensor does not match the moment variations through the critical point. The model also accounts semi-quantitatively for other experimental data previously measured, such as the field dependence of the heat capacity, energy of the dispersionless inelastic modes and transition temperature.Comment: 7 pages; 8 figure

    Renormalization effects on the MSSM from a calculable model of a strongly coupled hidden sector

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    We investigate possible renormalization effects on the low-energy mass spectrum of the minimal supersymmetric standard model (MSSM), using a calculable model of strongly coupled hidden sector. We model the hidden sector by N=2 supersymmetric quantum chromodynamics with gauge group SU(2) x U(1) and N_f=2 matter hypermultiplets, perturbed by a Fayet-Iliopoulos term which breaks the supersymmetry down to N=0 on a metastable vacuum. In the hidden sector the Kahler potential is renormalized. Upon identifying a hidden sector modulus with the renormalization scale, and extrapolating to the strongly coupled regime using the Seiberg-Witten solution, the contribution from the hidden sector to the MSSM renormalization group flows is computed. For concreteness, we consider a model in which the renormalization effects are communicated to the MSSM sector via gauge mediation. In contrast to the perturbative toy examples of hidden sector renormalization studied in the literature, we find that our strongly coupled model exhibits rather intricate effects on the MSSM soft scalar mass spectrum, depending on how the hidden sector fields are coupled to the messenger fields. This model provides a concrete example in which the low-energy spectrum of MSSM particles that are expected to be accessible in collider experiments is obtained using strongly coupled hidden sector dynamics.Comment: 18 pages, 11 figures, REVTeX4. Essentially the published versio

    Channel Capacity Enhancement by Pattern Controlled Handset Antenna

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    This paper presents a radiation pattern controlled antenna for handset terminals to reduce the correlation coefficient between antennas and enhance the channel capacity in MIMO applications. A pair of small inverted-F shaped antennas combined by a phase shifter provides a single port with controlled pattern. To enhance the channel capacity, the phase difference for the IFA array is optimized using the evaluation parameter of reception level, correlation coefficient and mean effective gain of the proposed array geometry. The channel capacity enhancement is verified by assuming Croneker scattering under Nakagami-Rice propagation model

    <Session 2: Fish Telemetry II>Homing behaviour of black rockfish

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    19–22 May 2021 Kyoto, JapanA lot of rockfish in the genus Sebastes exhibit distinctive homing ability. They can return back to an original location after displacement of metres or even kilometres. The black rockfish S. cheni is a site-specific fish, and shows homing to their original habitat after displacement. Using highresolution acoustic telemetry, we monitored homing behavior of the eight rockfish. The results demonstrated that they spent their time around the release site, and during this period they moved in the upstream and/or downstream direction. Then they gradually returning to their familiar area, and finally showed directed movements to the original habitat
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