Macroscopic quantum damping in SQUID rings

The measurement process is introduced in the dynamics of Josephson devices exhibiting quantum behaviour in a macroscopic degree of freedom. The measurement is shown to give rise to a dynamical damping mechanism whose experimental observability could be relevant to understand decoherence in macroscopic quantum systems.Comment: 7 Pages; Plain REVTeX; 3 Figures available upon request; to be published in Phys. Lett. A 229, 23 (1997

Four-dimensional understanding of quantum mechanics and Bell violation

While our natural intuition suggests us that we live in 3D space evolving in time, modern physics presents fundamentally different picture: 4D spacetime, Einstein's block universe, in which we travel in thermodynamically emphasized direction: arrow of time. Suggestions for such nonintuitive and nonlocal living in kind of "4D jello" come among others from: Lagrangian mechanics we use from QFT to GR saying that history between fixed past and future situation is the one optimizing action, special relativity saying that different velocity observers have different present 3D hypersurface and time direction, general relativity deforming shape of the entire spacetime up to switching time and space below the black hole event horizon, or the CPT theorem concluding fundamental symmetry between past and future. Accepting this nonintuitive living in 4D spacetime: with present moment being in equilibrium between past and future - minimizing tension as action of Lagrangian, leads to crucial surprising differences from intuitive "evolving 3D" picture, in which we for example conclude satisfaction of Bell inequalities - violated by the real physics. Specifically, particle in spacetime becomes own trajectory: 1D submanifold of 4D, making that statistical physics should consider ensembles like Boltzmann distribution among entire paths, what leads to quantum behavior as we know from Feynman's Euclidean path integrals or similar Maximal Entropy Random Walk (MERW). It results for example in Anderson localization, or the Born rule with squares - allowing for violation of Bell inequalities. Specifically, quantum amplitude turns out to describe probability at the end of half-spacetime from a given moment toward past or future, to randomly get some value of measurement we need to "draw it" from both time directions, getting the squares of Born rules.Comment: 13 pages, 18 figure

Stability of the Ground State of a Harmonic Oscillator in a Monochromatic Wave

Classical and quantum dynamics of a harmonic oscillator in a monochromatic wave is studied in the exact resonance and near resonance cases. This model describes, in particular, a dynamics of a cold ion trapped in a linear ion trap and interacting with two lasers fields with close frequencies. Analytically and numerically a stability of the ``classical ground state'' (CGS) -- the vicinity of the point ($x=0, p=0$) -- is analyzed. In the quantum case, the method for studying a stability of the quantum ground state (QGS) is suggested, based on the quasienergy representation. The dynamics depends on four parameters: the detuning from the resonance, $\delta=\ell-\Omega/\omega$, where $\Omega$ and $\omega$ are, respectively, the wave and the oscillator's frequencies; the positive integer (resonance) number, $\ell$; the dimensionless Planck constant, $h$, and the dimensionless wave amplitude, $\epsilon$. For $\delta=0$, the CGS and the QGS are unstable for resonance numbers $\ell=1, 2$. For small $\epsilon$, the QGS becomes more stable with increasing $\delta$ and decreasing $h$. When $\epsilon$ increases, the influence of chaos on the stability of the QGS is analyzed for different parameters of the model, $\ell$, $\delta$ and $h$.Comment: RevTeX, 38 pages, 24 figure

Stability of Chiral States, Role of Intermolecular Interactions and Molecular Parity Violation

We study the problem of stability of chiral states, also known as problem of chirality, within the framework of a two-dimensional approximation of a symmetric double-well potential. We show how the symmetry breaking of the potential due to the molecular parity violation can stop the tunneling in a coherent way, accordingly stabilize the chiral states. Then, we use the quantum Brownian motion within a linear Lindblad-type equation to model how the intermolecular interactions make the tunneling incoherent, thus inducing a racemization by dephasing. Finally, we investigate the normal physical conditions where the dephasing racemization does not suppress the effects of the molecular parity violation, accordingly the molecular parity violation may be observed experimentally.Comment: 5 pages, 2 Figure