Sat, 26 Jul 2008 00:41:34 BST CiteULike: norris quantum http://www.citeulike.org/user/norris/tag/quantum CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/norris/article/1666241 <i>(5 Jul 2006)</i><br /><br />anomechanical resonators having small mass, high resonance frequency and low damping rate are widely employed as mass detectors. We study the performances of such a detector when the resonator is driven into a region of nonlinear oscillations. We predict theoretically that in this region the system acts as a phase-sensitive mechanical amplifier. This behavior can be exploited to achieve noise squeezing in the output signal when homodyne detection is employed for readout. We show that mass sensitivity of the device in this region may exceed the upper bound imposed by thermomechanical noise upon the sensitivity when operating in the linear region. On the other hand, we show that the high mass sensitivity is accompanied by a slowing down of the response of the system to a change in the mass. Mass Detection with Nonlinear Nanomechanical Resonator Eyal Buks Bernard Yurke (5 Jul 2006) 2007-09-17T15:08:46-00:00 2006 quantum http://www.citeulike.org/user/norris/article/1525527 <i>Journal of Mathematical Physics, Vol. 13, No. 5. (1972), pp. 784-796.</i><br /><br />In this paper we evaluate several Feynman path integrals asymptotically with respect to various parameters in order to gain mathematical insight into the asymptotic evaluation of function space integrals with oscillatory integrands, a type of integral which is beginning to appear in areas of physics other than quantum mechanics. In each integral studied, the integrand factors into a product of two functionals, one of which is dominant in the limit under consideration. By systematically exploiting this feature, we obtain the asymptotic behavior of path integrals for the physical situations of (1) weakly complex potentials, (2) high energy and complex potentials, (3) weak real potentials, and (4) strong real potentials. In the complex cases, the techniques indicate a means to handle (complex valued) turning points. In the sections treating strong and weak potentials, we relate the relative ease with which one may exploit the factorization of the integrand to the theories of regular and singular perturbations. In the singular case, several examples are presented, one of which is a high energy evaluation of the path integral associated with the “Langer transformed” radial equation. Finally, using more conventional techniques, we construct the complete asymptotic series for each case, thus formally establishing that we have obtained the leading term in an asymptotic expansion of the path integral. ©1972 The American Institute of Physics Path Integrals, Asymptotics, and Singular Perturbations David Mclaughlin doi:10.1063/1.1666052 Journal of Mathematical Physics, Vol. 13, No. 5. (1972), pp. 784-796. 2007-07-31T17:22:01-00:00 1972 Journal of Mathematical Physics 13 5 784 796 AIP quantum http://www.citeulike.org/user/norris/article/1525522 <i>The American Mathematical Monthly, Vol. 82, No. 5. (1975), pp. 451-465.</i> The Feynman Integral JB Keller DW Mclaughlin The American Mathematical Monthly, Vol. 82, No. 5. (1975), pp. 451-465. 2007-07-31T17:18:44-00:00 1975 The American Mathematical Monthly 82 5 451 465 quantum http://www.citeulike.org/user/norris/article/1074601 <i>Applied Physics Letters, Vol. 88, No. 14. (2006)</i><br /><br />Two-dimensional arrays of coupled nanomechanical plate-type resonators were fabricated in single crystal silicon using e-beam lithography. Collective modes were studied using a double laser setup with independent positioning of the point laser drive and interferometric motion detector. The formation of a wide acoustic band has been demonstrated. Localization due to disorder (mistune) was identified as a parameter that limits the propagation of the elastic waves. We show that all 400 resonators in our 20×20 array participate in the extended modes and estimate group velocity and density of states. Applications utilizing the resonator arrays for radio frequency signal processing are discussed. ©2006 American Institute of Physics Two-dimensional array of coupled nanomechanical resonators Maxim Zalalutdinov Jeffrey Baldwin Martin Marcus Robert Reichenbach Jeevak Parpia Brian Houston doi:10.1063/1.2190448 Applied Physics Letters, Vol. 88, No. 14. (2006) 2007-01-29T15:54:40-00:00 2006 Applied Physics Letters 88 14 AIP damping phonons quantum http://www.citeulike.org/user/norris/article/989970 <i>(20 Nov 2006)</i><br /><br />We quantize the elastic modes in a plate. For this, we find a complete, orthogonal set of eigenfunctions of the elastic equations and we normalize them. These are the phonon modes in the plate and their specific forms and dispersion relations are manifested in low temperature experiments in ultra-thin membranes. Quantization of the elastic modes in an isotropic plate T Kühn DV Anghel (20 Nov 2006) 2006-12-12T17:12:48-00:00 2006 quantum http://www.citeulike.org/user/norris/article/802252 <i>Physical Review A, Vol. 29, No. 3. (March 1984), 1419.</i><br /><br />A general approach; within the framework of canonical quantization; is described for analyzing the quantum behavior of complicated electronic circuits. This approach is capable of dealing with electrical networks having nonlinear or dissipative elements. The techniques are applied to circuits capable of generating squeezed-state or two-photon coherent-state signals. Circuits capable of performing back-action-evading electrical measurements are also discussed. Quantum network theory Bernard Yurke John Denker doi:10.1103/PhysRevA.29.1419 Physical Review A, Vol. 29, No. 3. (March 1984), 1419. 2006-08-15T17:04:58-00:00 1984 Physical Review A 29 3 1419 American Physical Society quantum