We develop a consistent model of a quantum damped harmonic oscillator with arbitrary time-dependent frequency and damping coefficients within the framework of the Heisenberg–Langevin equations with two noncommuting delta-correlated noise operators justifying the choice of the “minimal noise” set of damping coefficients and correlation functions.

In electrodynamics there is a mutual exchange of energy and momentum between the matter field and the electromagnetic field and the total energy and momentum are conserved. For a constant magnetic field and harmonic scalar potential, electrodynamics is shown to be isomorph to a system of damped/amplified harmonic oscillators. These can be described by squeezed coherent states which in turn are ...

This paper investigates the lock range of injection-locked non-harmonic oscillators using a frequency-domain approach. By representing a non-harmonic oscillator with a set of harmonic oscillators, the intrinsic relation between the lock range of the harmonic oscillators and that of the non-harmonic is obtained. We show that non-harmonic oscillators exhibit a larger lock range as compared with h...

This paper presents a 20 GHz push-push VCO realized by a 10 GHz super-harmonic coupled quadrature oscillator for a quadrature 60 GHz frequency synthesizer. The output nodes are peaked by a tunable second harmonic resonator. The proposed VCO is implemented in 65 nm CMOS process. It achieves a tuning range of 3.5 GHz from 16.1 GHz to 19.6 GHz with a phase noise of −106 dBc/Hz at 1 MHz offset. The...

It is shown that the classical damped harmonic oscillator belongs to family of fourth-order Pais-Uhlenbeck oscillators. follows solutions equation make action stationary. Two systematic approaches are given for deriving from equation, and it may be possible use these methods identify stationary principles other dissipative systems which do not conform Hamilton's principle. also every $x$, there...

a direct conversion modulator-demodulator with even harmonic mixers with emphasis on noise analysis is presented. the circuits consist of even harmonic mixers (ehms) realized with antiparallel diode pairs (apdps). we evaluate the different levels of i/q imbalances and dc offsets and use signal space concepts to analyze the bit error rate (ber) of the proposed transceiver using m-ary qam schemes...

We propose a method for reconstruction of the density matrix from measurable time-dependent (probability) distributions of physical quantities. The applicability of the method based on least-squares inversion is – compared with other methods – very universal. It can be used to reconstruct quantum states of various systems, such as harmonic and and anharmonic oscillators including molecular vibr...

We have used Terahertz time-domain spectroscopy (THz-TDS) to investigate the complex dielectric function of water solutions containing different ions. Using HCl and NaCl solutions with different concentrations we study the changes of the dielectric response introduced by the ions. We find a linear increase of the real and imaginary part of the dielectric function compared with pure water with i...

We study a problem of energy exchange in a system of two coupled oscillators subject to 1 : 1 resonance. Our results exploit the concept of limiting phase trajectories LPTs . The LPT, associated with full energy transfer, is, in certain sense, an alternative to nonlinear normal modes characterized by conservation of energy. We consider two benchmark examples. As a first example, we construct an...

(Dated: February 2, 2008) The effect of thermal fluctuations in the resonance fluorescence of a three-level system is studied. The damped three-level system is driven by two strong incident classical fields near resonances frequencies. The simulation of a thermal bath is obtained with a large system of harmonic oscillators that represent the normal modes of the thermal radiation field. The time...