309 research outputs found
Observing Coherence Effects in an Overdamped Quantum System
It is usually considered that the spectrum of an optical cavity coupled to an
atomic medium does not exhibit a normal-mode splitting unless the system
satisfies the strong coupling condition, meaning the Rabi frequency of the
coherent coupling exceeds the decay rates of atom and cavity excitations. Here
we show that this need not be the case, but depends on the way in which the
coupled system is probed. Measurements of the reflection of a probe laser from
the input mirror of an overdamped cavity reveal an avoided crossing in the
spectrum which is not observed when driving the atoms directly and measuring
the Purcell-enhanced cavity emission. We understand these observations by
noting a formal correspondence with electromagnetically-induced transparency of
a three-level atom in free space, where our cavity acts as the absorbing medium
and the coupled atoms play the role of the control field
Характеристика лавиноопасных участков на перегоне Дебильчинда-Дабан-Гоуджекит Восточно-Сибирской железной дороги
Metacognitive improvement and symptom change in a 3-month treatment for borderline personality disorder.
Recognizing and reflecting on one's own and other people's mental states represent a major difficulty for patients with borderline personality disorder (BPD). Only recently have studies begun exploring whether these capacities increase with successful therapies and if such an improvement is linked with outcome. The present study investigated whether metacognition would improve and if its improvement was related with symptom change in BPD patients.
The transcripts from the first and the penultimate session of a ten-session version of good psychiatric management were analysed with the MAS-R scale in a N = 37 BPD sample. Patients, selected from a previously published RCT (Kramer et al., 2014), were assigned either to the good psychiatric management treatment or to the same treatment with the addition of the Motive-Oriented Therapeutic Relationship (Caspar, 2007), a form of therapeutic relationship based on an individualized case formulation. Symptoms were assessed with the OQ-45.
Findings partially support the hypotheses. First, improvement in capacities to understand others' mind, to take a critical distance from one's own rigid and maladaptive beliefs, and to use behavioural and attentional strategies to face adversities is found in both treatment groups. Controlling for marital status, only the ability to differentiate between reality and representations remains significant. Second, no link between metacognitive change and symptom change during treatment is found. However, a link is observed between the increase in metacognition and symptom reduction at 6-month follow-up.
Results invite to further investigate the role of metacognition in therapy change through different modalities and in longer-term treatments.
The development of metacognitive processes and their links with symptom change were examined during a short-term treatment in 37 borderline patients Improvement was found in capacities to understand others' mind, to take a critical distance from own rigid and maladaptive beliefs, and to use behavioural and attentional strategies even in a short-term treatment Controlling for marital status, only the ability to take a critical distance from representations remained significant A link was observed between increase in metacognition and symptom reduction at 6-month follow-up Understanding and tailoring interventions to specific metacognitive difficulties could be associated with symptom change during treatment for BPD patients
Ultrahigh Vacuum Packaging and Surface Cleaning for Quantum Devices
We describe design, implementation and performance of an ultra-high vacuum
(UHV) package for superconducting qubit chips or other surface sensitive
quantum devices. The UHV loading procedure allows for annealing, ultra-violet
light irradiation, ion milling and surface passivation of quantum devices
before sealing them into a measurement package. The package retains vacuum
during the transfer to cryogenic temperatures by active pumping with a titanium
getter layer. We characterize the treatment capabilities of the system and
present measurements of flux tunable qubits with an average Ts and
Ts after vacuum-loading these samples into a bottom loading
dilution refrigerator in the UHV-package.Comment: 5 pages, 6 figure
Hyperfine and Spin-Orbit Coupling Effects on Decay of Spin-Valley States in a Carbon Nanotube
The decay of spin-valley states is studied in a suspended carbon nanotube double quantum dot via the leakage current in Pauli blockade and via dephasing and decoherence of a qubit. From the magnetic field dependence of the leakage current, hyperfine and spin-orbit contributions to relaxation from blocked to unblocked states are identified and explained quantitatively by means of a simple model. The observed qubit dephasing rate is consistent with the hyperfine coupling strength extracted from this model and inconsistent with dephasing from charge noise. However, the qubit coherence time, although longer than previously achieved, is probably still limited by charge noise in the device. © 2017 American Physical Society
Nitrogen Species in the Post-Pinatubo Stratosphere: Model Analysis Utilizing UARS Measurements
We present an analysis of the impact of heterogeneous chemistry on the partitioning of nitrogen species measured by the Upper Atmosphere Research Satellite (UARS) instruments. The UARS measurements utilized include: N2O, HNO3 and ClONO2 (Cryogen Limb Array Etalon Spectrometer (CLAES), version 7), temperature, methane, ozone, H2O, HCl, NO and NO2 (HALogen Occultation Experiment (HALOE), version 18). The analysis is carried out for the data from January 1992 to September 1994 in the 100-1 mbar (approx.17-47 km) altitude range and over 10 degree latitude bins from 70degS to 70degN. Temporal-spatial evolution of aerosol surface area density (SAD) is adopted according to the Stratospheric Aerosol and Gas Experiment (SAGE) 11 data. A diurnal steady-state photochemical box model, constrained by the temperature, ozone, H2O, CH4, aerosol SAD and columns of O2 and O3 above the point of interest, has been used as the main tool to analyze these data. Total inorganic nitrogen (NO(y)) is obtained by three different methods: (1) as a sum of the UARS measured NO, NO2, HNO3, and ClONO2; (2) from the N2O-NO(y) correlation, and (3) from the CH4-NO(y) correlation. To validate our current understanding of stratospheric heterogeneous chemistry for post-Pinatubo conditions, the model-calculated NO(x)/NO(y) ratios and the NO, NO2, and HNO3 profiles are compared to the UARS-derived data. In general, the UARS-constrained box model captures the main features of nitrogen species partitioning in the post-Pinatubo years. However, the model underestimates the NO2 content, particularly, in the 30-7 mbar (approx. 23-32 km) range. Comparisons of the calculated temporal behavior of the partial columns of NO2 and HNO3 and ground based measurements at 45degS and 45degN are also presented. Our analysis indicates that ground-based and HALOE v. 18 measurements of the NO2 vertical columns are consistent within the range of their uncertainties and are systematically higher (up to 50%) than the model results at mid-latitudes in both hemispheres. Reasonable agreement is obtained for HNO3 columns at 45degS suggesting some problems with nitrogen species partitioning in the model. Outstanding uncertainties are discussed
Changes in V1 orientation tuning when blocking astrocytic glutamate transporters: models for extra- and intrasynaptic mechanisms
ГЛАГОЛЫ ДВИЖЕНИЯ РУССКОГО ЯЗЫКА (сборник таблиц и упражнений слушателям подготовительного отделения для иностранных граждан)
Представлены русские глаголы, обозначающие способы передвижения в
пространстве, формы и случаи употребления глаголов движения в языке для изучения иностранными студентами подготовительного отделения (сборник
таблиц и упражнений)
Impact of interface traps on charge noise, mobility and percolation density in Ge/SiGe heterostructures
Hole spins in Ge/SiGe heterostructure quantum dots have emerged as promising
qubits for quantum computation. The strong spin-orbit coupling (SOC),
characteristic of heavy-hole states in Ge, enables fast and all-electrical
qubit control. However, SOC also increases the susceptibility of spin qubits to
charge noise. While qubit coherence can be significantly improved by operating
at sweet spots with reduced hyperfine or charge noise sensitivity, the latter
ultimately limits coherence, underlining the importance of understanding and
reducing charge noise at its source. In this work, we study the voltage-induced
hysteresis commonly observed in SiGe-based quantum devices and show that the
dominant charge fluctuators are localized at the semiconductor-oxide interface.
By applying increasingly negative gate voltages to Hall bar and quantum dot
devices, we investigate how the hysteretic filling of interface traps impacts
transport metrics and charge noise. We find that the gate-induced accumulation
and trapping of charge at the SiGe-oxide interface leads to an increased
electrostatic disorder, as probed by transport measurements, as well as the
activation of low-frequency relaxation dynamics, resulting in slow drifts and
increased charge noise levels. Our results highlight the importance of a
conservative device tuning strategy and reveal the critical role of the
semiconductor-oxide interface in SiGe heterostructures for spin qubit
applications
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