(Pdf) testing wavefunction collapse models using parametric heating of a trapped nanosphere electricity schoolhouse rock


We study the stochastic dynamics of a particle subject to a periodically driven potential. For atomic ions trapped in radio-frequency Paul traps, noise heating and laser cooling typically act slowly in comparison with the timescale of the unperturbed motion. These stochastic processes can be accounted for in terms of a probability distribution defined over the action variables, that would otherwise be conserved within the regular regions of the Hamiltonian phase-space. We present electricity bill payment hyderabad a semiclassical theory of low saturation laser cooling applicable from the limit of low amplitude motion to large amplitude motion, accounting fully for the time-dependence of the trap. We employ our approach to a detailed study of the stochastic dynamics of an ion in the different regimes of motion within an anharmonic radio-frequency Paul trap, drawing general conclusions regarding the nonequilibrium dynamics of trapped ions. We predict a regime of anharmonic motion with laser cooling becoming diffusive (i.e. it is equally likely to cool the ion as it is to heat it), and also turning into an effective heating. Such a mechanism implies that an ion in a high kinetic energy state may be easily lost from the trap despite being laser cooled, however we find that such loses can be counteracted using a large laser detuning. More generally, the presented theory applies to a broad range of periodically driven systems and out-of-equilibrium stochastic dynamics.

Collapse gas usa models postulate that space is filled with a collapse noise field, inducing quantum Brownian motions, which are dominant during the measurement, thus causing collapse of the wave function. An important manifestation of the collapse noise field, if any, is thermal energy generation, thus disturbing the temperature profile of a system. The experimental investigation of a collapse-driven heating effect has provided, so far, the most promising test of collapse models against standard quantum theory. In this paper, we calculate the collapse-driven heat generation for a three-dimensional multi-atomic Bravais lattice by solving stochastic Heisenberg equations. We perform our calculation for the mass-proportional continuous spontaneous localization collapse e sampark electricity bill payment model with nonwhite noise. We obtain the temperature distribution of a sphere under stationary-state and insulated surface conditions. However, the exact quantification of the collapse-driven heat-generation effect highly depends on the actual value of cutoff in the collapse noise spectrum.

Levitated optomechanical systems, and particularly particles trapped in vacuum, provide unique platforms for studying the mechanical behavior of objects well-isolated from their environment. Ultimately, such systems may enable the study of fundamental questions in quantum mechanics, gravity, and other weak forces. While the optical trapping of nanoparticles has emerged as the prototypical levitated optomechanical system, it is not without problems due to the heating from the high optical intensity required, particularly when combined with a high vacuum environment. Here we investigate a magneto-gravitational trap in ultra-high vacuum. In contrast to optical trapping, we create an entirely passive trap for diamagnetic particles by utilizing the magnetic field generated by permanent magnets and the gravitational interaction. We demonstrate cooling the center of mass motion of a trapped silica microsphere from ambient temperature to an effective ideal gas definition chemistry temperature near or below one milliKelvin in two degrees of freedom by optical feedback damping.

We discuss limits on the noise strength parameter in mass-proportional-coupled wave-function collapse models implied by bulk heating effects and examine the role of the noise power spectrum in comparing experiments of different types. This comparison utilizes a calculation of the rate of heating through phonon excitation implied by a general noise power spectrum λ(ω). We find that, in the standard heating formula, the reduction rate λ is replaced by λeff=23π3/2∫d3we electricity definition physics−w⃗2w⃗2λ(ωL(w⃗/rc)), with ωL(q⃗) being the longitudinal acoustic-phonon frequency as a function of wave number q⃗, and with rC being the noise correlation length. Hence if the noise power spectrum is cut off below ωL(|q⃗|∼rc−1), the bulk heating rate is sharply reduced, allowing compatibility with current experimental results. We suggest possible new bulk heating experiments that can be performed subject to limits placed by natural heating from radioactivity and cosmic rays. The proposed experiments exploit the vanishing of thermal transport in the low-temperature limit.

Levitated optomechanics, a new experimental physics platform, holds promise for fundamental science and quantum technological sensing applications. We demonstrate a simple and robust geometry for optical trapping in vacuum of a single nanoparticle based on a parabolic mirror and the optical gradient force. We demonstrate parametric feedback cooling of all three motional degrees of freedom from room temperature to a few millikelvin. A single laser at 1550 nm and a single photodiode are used for trapping, position detection, and cooling for all three dimensions. Particles with diameters from 26 to 160 nm are trapped without feedback to 10⁻⁵ mbar, and electricity cost per month with feedback-engaged, the pressure is reduced to 10⁻⁶ mbar. Modifications to the harmonic motion in the presence of noise and feedback are studied, and an experimental mechanical quality factor in excess of 4 × 10⁷ is evaluated. This particle manipulation is key to building a nanoparticle matter-wave interferometer in order to test the quantum superposition principle in the macroscopic domain.

The observation that all objects in our universe interact with each other to a greater or lesser degree seems rather trivial at first sight. The strength, and thereby the consequences, of interactions vary arkansas gas tax enormously, depending on the situation considered. Sometimes, even in the framework of classical physics, surprising results have been found. A prominent example, already mentioned in Sect. 2.3, is the influence of a small mass of a few grams, as far away as the star Sirius, on the trajectories of air molecules here on earth (Borel 1914a, Brillouin 1964) . This example demonstrates that even a coupling which is considered as weak (as gravity certainly is over such distances) can have a great influence on systems that are sensitive enough to this kind of interaction, “The representation of gaseous matter… composed of molecules with positions and velocities which are rigorously determined at a given instant is therefore a pure abstract fiction;… as soon as one supposes a shell gas station near me the indeterminacy of the external forces, the effect of collisions will very rapidly disperse the trajectory bundles which are supposed to be infinitely narrow, and the problem of the subsequent movement of the molecules becomes, within a few seconds, very indeterminate, in the sense that an enormously large number of different possibilities are a priori equally probable.”1 (Borel 1914b)

We set up a general formalism for models of spontaneous wave function collapse with dynamics represented by a stochastic differential equation driven by general Gaussian noises, not necessarily electricity symbols and units white in time. In particular, we show that the non-Schrodinger terms of the equation induce the collapse of the wave function to one of the common eigenstates of the collapsing operators, and that the collapse occurs with the correct quantum probabilities. We also develop a perturbation expansion of the solution of the equation with respect to the parameter which sets the strength of the collapse process; such an approximation allows one to compute the leading order terms for the deviations of the predictions of collapse models with respect to those of standard quantum mechanics. This analysis shows that to leading order, the “imaginary” noise trick can be used for non-white Gaussian noise. Comment: Latex, 20 pages;references added and minor revisions; published as J. Phys. A: Math. Theor. {\bf 40} (2007) 15083-15098

Wavefunction gas kinetic energy collapse models modify Schrodinger’s equation so that it describes the rapid evolution of a superposition of macroscopically distinguishable states to one of them. This provides a phenomenological basis for a physical resolution to the so-called measurement problem. Such models have experimentally testable differences from standard quantum theory. The most well developed such model at present is the Continuous Spontaneous Localization (CSL) model in which a fluctuating classical field interacts with particles to cause collapse. One side effect of this interaction is that the field imparts momentum to particles, causing a small blob of matter to undergo random walk. Here we explore this in order to supply predictions which could be experimentally tested. We examine the translational diffusion of a sphere and a disc, and the rotational diffusion of a disc, according to CSL. For example, we find that a disc of radius 2 cdot 10^{-5} cm and thickness 0.5 cdot 10^{-5} cm diffuses through 2 pi rad in about 70sec (this assumes the standard CSL parameter values). The comparable rms diffusion of standard quantum theory is smaller than this by a factor 10^-3. At the reported pressure of 5 cdot10^{-17} Torr, achieved at 4.2^{circ} K, the mean time between air molecule collisions with the disc is approximately 45min (and the diffusion caused by photon collisons is utterly negligible). This is ample time for observation of the putative CSL diffusion over a wide range of parameters. This encourages consideration of how such an experiment may actually be performed, and the paper closes gas density formula with some thoughts on this subject