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Small-Scale Turbulence In A Closed-Field-Line Geometry, Paolo Ricci, B. N. Rogers, W. Dorland
Small-Scale Turbulence In A Closed-Field-Line Geometry, Paolo Ricci, B. N. Rogers, W. Dorland
Dartmouth Scholarship
Plasma turbulence due to small-scale entropy modes is studied with gyrokinetic simulations in a simple closed-field-line geometry, the Z pinch, in low-β parameter regimes that are stable to ideal interchange modes. We find an enormous variation in the nonlinear dynamics and particle transport as a function of two main parameters, the density gradient and the plasma collisionality. This variation is explained in part by the damping and stability properties of spontaneously formed zonal flows in the system. As in toroidal systems, the zonal flows can lead to a strong nonlinear suppression of transport below a critical gradient that is determined …
Single-Bit Feedback And Quantum-Dynamical Decoupling, Francesco Ticozzi, Lorenza Viola
Single-Bit Feedback And Quantum-Dynamical Decoupling, Francesco Ticozzi, Lorenza Viola
Dartmouth Scholarship
Synthesizing an effective identity evolution in a target system subjected to unwanted unitary or nonunitary dynamics is a fundamental task for both quantum control and quantum information processing applications. Here, we investigate how single-bit, discrete-time feedback capabilities may be exploited to enact or to enhance quantum procedures for effectively suppressing unwanted dynamics in a finite-dimensional open quantum system. An explicit characterization of the joint unitary propagators correctable by a single-bit feedback strategy for arbitrary evolution time is obtained. For a two-dimensional target system, we show how by appropriately combining quantum feedback with dynamical decoupling methods, concatenated feedback-decoupling schemes may be …
Exact Casimir Interaction Between Eccentric Cylinders, D. A. R. Dalvit, F. C. Lombardo, F. D. Mazzitelli, R. Onofrio
Exact Casimir Interaction Between Eccentric Cylinders, D. A. R. Dalvit, F. C. Lombardo, F. D. Mazzitelli, R. Onofrio
Dartmouth Scholarship
The Casimir force is the ultimate background in ongoing searches for extragravitational forces in the micrometer range. Eccentric cylinders offer favorable experimental conditions for such measurements as spurious gravitational and electrostatic effects can be minimized. Here we report on the evaluation of the exact Casimir interaction between perfectly conducting eccentric cylinders using a mode summation technique, and study different limiting cases of relevance for Casimir force measurements, with potential implications for the understanding of mechanical properties of nanotubes.
Detectability Of Dissipative Motion In Quantum Vacuum Via Superradiance, Woo-Joong Kim, James Hayden Brownell, Roberto Onofrio
Detectability Of Dissipative Motion In Quantum Vacuum Via Superradiance, Woo-Joong Kim, James Hayden Brownell, Roberto Onofrio
Dartmouth Scholarship
We propose an experiment for generating and detecting vacuum-induced dissipative motion. A high frequency mechanical resonator driven in resonance is expected to dissipate mechanical energy in quantum vacuum via photon emission. The photons are stored in a high quality electromagnetic cavity and detected through their interaction with ultracold alkali-metal atoms prepared in an inverted population of hyperfine states. Superradiant amplification of the generated photons results in a detectable radio- frequency signal temporally distinguishable from the expected background.