Quantum Energy Teleportation between Spin Particles in a Gibbs State

Energy in a multipartite quantum system appears from an operational perspective to be distributed to some extent non-locally because of correlations extant among the system's components. This non-locality allows users to transfer, in effect, locally accessible energy between sites of different system components by LOCC (local operations and classical communication). Quantum energy teleportation is a three-step LOCC protocol, accomplished without an external energy carrier, for effectively transferring energy between two physically separated, but correlated, sites. We apply this LOCC teleportation protocol to a model Heisenberg spin particle pair initially in a quantum thermal Gibbs state, making temperature an explicit parameter. We find in this setting that energy teleportation is possible at any temperature, even at temperatures above the threshold where the particles' entanglement vanishes. This shows for Gibbs spin states that entanglement is not fundamentally necessary for energy teleportation; correlation other than entanglement can suffice. Dissonance---quantum correlation in separable states---is in this regard shown to be a quantum resource for energy teleportation, more dissonance being consistently associated with greater energy yield. We compare energy teleportation from particle A to B in Gibbs states with direct local energy extraction by a general quantum operation on B and find a temperature threshold below which energy extraction by a local operation is impossible. This threshold delineates essentially two regimes: a high temperature regime where entanglement vanishes and the teleportation generated by other quantum correlations yields only vanishingly little energy relative to local extraction and a second low-temperature teleportation regime where energy is available at B only by teleportation

Probing the qudit depolarizing channel

For the quantum depolarizing channel with any finite dimension, we compare three schemes for channel identification: unentangled probes, probes maximally entangled with an external ancilla, and maximally entangled probe pairs. This comparison includes cases where the ancilla is itself depolarizing and where the probe is circulated back through the channel before measurement. Compared on the basis of (quantum Fisher) information gained per channel use, we find broadly that entanglement with an ancilla dominates the other two schemes, but only if entanglement is cheap relative to the cost per channel use and only if the external ancilla is well shielded from depolarization. We arrive at these results by a relatively simple analytical means. A separate, more complicated analysis for partially entangled probes shows for the qudit depolarizing channel that any amount of probe entanglement is advantageous and that the greatest advantage comes with maximal entanglement

Local Support Assembly of the ATLAS Pixel Detector

The barrel part of the ATLAS pixel detector will consist of 112 carbon-carbon structures called "staves" with 13 hybrid detector modules being glued on each stave. The demands on the glue joints are high, both in terms of mechanical precision and thermal contact. To achieve this precision a custom-made semi-automated mounting machine has been constructed in Wuppertal, which provides a precision in the order of tens of microns. As this is the last stage of the detector assembly providing an opportunity for stringent tests, a detailed procedure has been defined for assessing both mechanical and electrical properties. This note gives an overview of the procedure for affixation and tests, and summarizes the first results of the production.Comment: 6 pages, 8 figure

Optical Readout in a Multi-Module System Test for the ATLAS Pixel Detector

The innermost part of the ATLAS experiment at the LHC, CERN, will be a pixel detector. The command messages and the readout data of the detector are transmitted over an optical data path. The readout chain consists of many components which are produced at several locations around the world, and must work together in the pixel detector. To verify that these parts are working together as expected a system test has been built up. In this paper the system test setup and the operation of the readout chain is described. Also, some results of tests using the final pixel detector readout chain are given.Comment: 6 pages, 10 figures, Pixel 2005 proceedings preprin

Changes in maize silage fermentation products during aerobic deterioration and effects on dry matter intake by goats

Chemical and microbiological changes occurring during aerobic exposure of maize silages and their influence on dry matter (DM) intake and preference by goats were evaluated. Eight maize silages differing in DM content, chopping length and compaction pressure were used for the study. After opening, silages were exposed to air for 8 days (d). In 2-d intervals, silage was stored anaerobically for use in preference trials. During the experimental phase, each possible two-way combination of the five silages (d0, d2, d4, d6 and d8) and one standard lucerne hay, was offered as free choice to six goats. Generally, a significant decline occurred in DM intake after 4 d of aerobic exposure. After 8 d, mean decrease in intake was 53% in comparison to the fresh silages. Preference when expressed as DM intake was negatively correlated to silage temperature (as difference to ambient), ethanol and ethyl lactate

Multistatic adaptive pulse compression

A new technique denoted as multistatic adaptive pulse compression (MAPC) is introduced which exploits recent work on adaptive pulse compression (APC) in order to jointly separate and pulse compress the concurrently received return signals from K proximate multistatic radars operating (i.e., transmitting) within the same spectrum. For the return signal from a single pulse of a monostatic radar, APC estimates the particular receive filter for a given range cell in a Bayesian sense reiteratively by employing the matched filter estimates of the surrounding range cell values as a priori knowledge in order to place temporal (i.e., range) nulls at the relative ranges occupied by large targets and thereby suppress range sidelobes to the level of the noise. The MAPC approach generalizes the APC concept by jointly estimating the particular receive filter for each range cell associated with each of several concurrently-received radar return signals occupying the same spectrum. As such, MAPC is found to enable shared-spectrum multistatic operation and is shown to yield substantial performance improvement in the presence of multiple spectrum-sharing radars as compared with both standard matched filters and standard least-squares mismatched filters

STAP using knowledge-aided covariance estimation and the FRACTA algorithm

In the airborne space-time adaptive processing (STAP) a priori information via knowledge-aided covariance estimation (KACE) is employed in order to reduce the required sample support for application to heterogeneous clutter scenarios. The enhanced FRACTA (FRACTAX) algorithm with KACE as well as Doppler-sensitive adaptive coherence estimation (DS-ACE) is applied to the KASSPER I & II data sets where it is shown via simulation that near-clairvoyant detection performance is maintained with as little as 1/3 of the normally required number of training data samples. The KASSPER I & II data sets are simulated high-fidelity heterogeneous clutter scenarios which possess several groups of dense targets. KACE provides a priori information about the clutter covariance matrix by exploiting approximately known operating parameters about the radar platform such as pulse repetition frequency (PRF), crab angle, and platform velocity. In addition, the DS-ACE detector is presented which provides greater robustness for low sample support by mitigating false alarms from undernulled clutter near the clutter ridge while maintaining sufficient sensitivity away from the clutter ridge to enable effective target detection performance

Alterations of nocturnal activity in rats following subchronic oral administration of the neurotoxin 1-trichloromethyl-1,2,3,4-tetrahydro-β-carboline

1-Trichloromethyl-1,2,3,4-tetrahydro-β-carboline (TaClo) is neurotoxic when administered to the brain and alters motor behaviour following intraperitoneal administration. We have assessed the long-term effects of oral TaClo administration on nocturnal motor behaviour in rats. Two groups of rats received TaClo orally at a dose of either 0.2 or 0.4 mg/kg twice daily for 7 weeks. The control group was given saline. No change in locomotor activity was observed 4–9 days after the end of the 7-week administration of TaClo. In addition, the spontaneous motor activity was altered dose-dependently 9 months after oral TaClo administration, with an increase in the low-dose TaClo group and a decrease in the high-dose group. Oral administration of TaClo in rats may be useful in investigating the hypothesis that in Parkinson’s disease, an unknown pathogenic factor crossing the intestinal mucosa barrier can induce neurodegenerative processes eventually affecting the entire brain