Imaginary Kapitza pendulum

Kapitza Pendulum: A Physically Transparent Simple Explanation

The phenomenon of dynamic stabilization of the inverted pendulum whose pivot is forced to oscillate with a high frequency in vertical direction is revisited. A simple physically meaningful explanation of the phenomenon is presented, followed by the derivation of an approximate quantitative criterion of stability. A computer program simulating the physical system is developed, which aids the ana...

Spin-dependent two-color Kapitza-Dirac effects

Theory of the Kapitza-Dirac diffraction effect.

We treat the Kapitza-Dirac diffraction effect observed recently by Batelaan et al. using a newly developed nonperturbative quantum-field scattering theory. Our theory shows that an electron beam passing perpendicularly through a focused standing light wave can produce diffraction patterns. Our theory predicts (1) the minimum value of the ponderomotive energy is (Planck's over 2 pi omega)(2)/m(e...

Appraisal of the Cmn/helium Kapitza Resistance

It is argued that the thermal resistance between cerium magnesium nitrate (CMN) and pure He,He containing He* impurity or dilute He in He"* can be understood in terms of the phonon bottlenecked spin-lattice resistance within the CMN and a size dependent thermal boundary resistivity. The fact that emerges is that the phonon bottleneck within the CMN is strongly dependent upon whether the CMN is ...

Kapitza Fall 2017 NOISY QUANTUM MEASUREMENT