Sat, 26 Jul 2008 06:24:05 BST CiteULike: dhbradshaw's nonlinear http://www.citeulike.org/user/dhbradshaw/tag/nonlinear CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/dhbradshaw/article/2641704 <i>Physical Review A, Vol. 55, No. 1. (January 1997), 678.</i><br /><br />Theories which have been used to describe the quantized electromagnetic field interacting with a nonlinear dielectric medium are either phenomenological or derived by quantizing the macroscopic Maxwell equations. Here we take a different approach and derive a Hamiltonian describing interacting fields from one which contains both field and matter degrees of freedom. The medium is modeled as a collection of two-level atoms; and these interact with the electromagnetic field. The atoms are grouped into effective spins and the the Holstein-Primakoff representation of the spin operators is used to expand them in inverse powers of the total spin. When the lowest order term of the interaction is combined with the free atomic and field Hamiltonians; a Hamiltonian describing a theory of noninteracting polaritons results. When higher order terms are expressed in terms of polariton operators standard nonlinear optical interactions emerge. These are then compared to the results of phenomenological and macroscopic theories. The theory is also used to derive an effective Hamiltonian describing counterpropagating modes in a nonlinear medium. Quantized fields in a nonlinear dielectric medium: A microscopic approach Mark Hillery Leonard Mlodinow doi:10.1103/PhysRevA.55.678 Physical Review A, Vol. 55, No. 1. (January 1997), 678. 2008-04-08T14:15:23-00:00 1997 Physical Review A 55 1 678 American Physical Society deutsch nonlinear http://www.citeulike.org/user/dhbradshaw/article/2567735 <i>Physical Review Letters, Vol. 71, No. 11. (1993), 1709.</i><br /><br />We propose and analyze a nonlinear optical amplifier that is phase insensitive but has no additive noise. When the input field is in a coherent state; the noise figure is -6 dB when the gain is high. However; unlike conventional linear amplifiers with -3 dB noise figures; the detectibility of the amplified signal is not degraded. The amplifier is constructed simply; in principle; by the same type of nonlinear interferometer used in photon number quantum nondemolition measurements. Quantum noise properties of a nonlinear amplifier RS Bondurant doi:10.1103/PhysRevLett.71.1709 Physical Review Letters, Vol. 71, No. 11. (1993), 1709. 2008-03-20T17:33:01-00:00 1993 Physical Review Letters 71 11 1709 American Physical Society measurement nonlinear quantum