37474263
Quantum control by compensation of quantum fluctuations.
We show that the influence of quantum fluctuations in the electromagnetic field vacuum on a two level atom can be measured and consequently compensated by balanced homodyne detection and a coherent feedback field. This compensation suppresses the decoherence associated with spontaneous emissions for a specific state of the atomic system allowing complete control of the coherent state of the system.
18424039
Quantum control of atomic systems by time resolved homodyne detection
We describe the light-matter interaction of a single two level atom with the electromagnetic vacuum in terms of field and dipole variables by considering homodyne detection of the emitted fields. Spontaneous emission is then observed as a continuous fluctuating force acting on the atomic dipole. The effect of this force may be compensated and even reversed by feedback.
14854411
Correlation between Correlations: Process and Time in Quantum Networks
We study a special inhomogeneous quantum network consisting of a ring of M pseudo-spins (here M = 4) sequentially coupled to one and the same central spin under the influence of given pulse sequences (quantum gate operations). This architecture could be visualized as a quantum Turing machine with a cyclic "tape". Rather than input-output-relations we investigate the resulting process, i.e. the correlation between one-and two-point expectation values ("correlations") over various time-steps. The resulting spatiotemporal pattern exhibits many non-classical features including Zeno-effects, violation of temporal Bell-inequalities and quantum parallelism. Due to the strange web of correlations being built-up, specific measurement outcomes for the tape may refer to one or several preparation histories of the head. Specific families of correlation functions are more stable with respect to dissipation than the total wave-function.
119369099
Quantum trajectories of interacting pseudo-spin networks

We consider quantum trajectories of composite systems as generated by the stochastic unraveling of the respective Lindblad-master-equation. Their classical limit is taken to correspond to local jumps between orthogonal states. Based on statistical distributions of jump- and inter-jump-distances we are able to quantify the non-classicality of quantum trajectories. To account for the operational effect of entanglement we introduce the novel concept of "co-jumps".
26164616
A new relative proton polarimeter for RHIC
An innovative polarimeter based on proton carbon elastic scattering in the Coulomb nuclear interference (CNI) region has been installed and commissioned in the Blue ring of RHIC during the first RHIC polarized proton commissioning in September, 2000. The polarimeter consists of ultra-thin C targets and four Si detectors. All elements are in a 1.6 meter vacuum chamber. This paper summarizes the polarimeter design issues and recent commissioning results.
32903269
Coherent electron cooling demonstration experiment
Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC. We plan to complete the program in five years. During first two years we will build coherent electron cooler in IP2 of RHIC. In parallel we will develop complete package of computer simulation tools for the start-to-end simulation predicting exact performance of a CeC. The later activity will be the core of Tech X involvement into the project. We will use these tools to predict the performance of our CeC device. The experimental demonstration of the CeC will be undertaken in years three to five ofmore » the project. The goal of this experiment is to demonstrate the cooling of ion beam and to compare its measured performance with predictions made by us prior to the experiments.« less
124191576
R&D energy recovery linac at brookhaven national laboratory
Collider Accelerator Department at BNL is in the final stages of developing the 20-MeV R and D energy recovery linac with super-conducting 2.5 MeV RF gun and single-mode super-conducting 5-cell RF linac. This unique facility aims to address many outstanding questions relevant for high current (up to 0.5 A of average current), high brightness energy-recovery linacs with novel ZigZag-type merger. Recent development in the R and D ERL plans include gun and 5-cell cavity (G5) test and possibility of using R and D ERL for proof-of-principle test of Coherent Electron Cooling at RHIC.