23,764 research outputs found
Rotation in galaxy clusters from MUSIC simulations with the kinetic Sunyaev-Zel'dovich effect
We propose in this work its application for the detection of possible coherent rotational motions in the hot intra-cluster medium. We select a sample of massive, relaxed and rotating galaxy clusters from Marenostrum-mUltidark SImulations of galaxy Clusters (MUSIC), and we produce mock maps of the temperature distortion produced by the kinetic Sunyaev-Zel'dovich effect by exploring six different lines of sight, in the best observational condition. These maps are compared with the expected signal computed from a suitable theoretical model in two cases: (i) focusing only on the contribution from the rotation, and (ii) accounting also for the cluster bulk motion. We find that the parameters of the model assumed for the radial profile of the rotational velocity, averaged over the considered lines of sight, are in agreement within two standard deviations at most with independent estimates from the simulation data, without being significantly affected by the presence of the cluster bulk term. The amplitude of the rotational signal is, on average, of the order of 23 per cent of the total signal accounting also for the cluster bulk motion, and its values are consistent with the literature. The projected bulk velocity of the cluster is also recovered at the different lines of sight, with values in agreement with the simulation dataASB acknowledges funding from Sapienza Università di Roma - Progetti per Avvio alla Ricerca Anno 2017, prot. AR11715C82402BC
Nonlinear dynamics of a cigar-shaped Bose-Einstein condensate coupled with a single cavity mode
We investigate the nonlinear dynamics of a combined system which is composed
of a cigar-shaped Bose-Einstein condensate and an optical cavity. The two sides
couple dispersively. This system is characterized by its nonlinearity: after
integrating out the freedom of the cavity mode, the potential felt by the
condensate depends on the condensate itself. We develop a discrete-mode
approximation for the condensate. Based on this approximation, we map out the
steady configurations of the system. It is found that due to the nonlinearity
of the system, the nonlinear levels of the system can fold up in some parameter
regimes. That will lead to the breakdown of adiabaticity. Analysis of the
dynamical stability of the steady states indicates that the same level
structure also results in optical bistability.Comment: 8 pages, 5 figure
Vector magnetic field sensing by single nitrogen vacancy center in diamond
In this Letter, we proposed and experimentally demonstrated a method to
detect vector magnetic field with a single nitrogen vacancy (NV) center in
diamond. The magnetic field in parallel with the axis of the NV center can be
obtained by detecting the electron Zeeman shift, while the Larmor precession of
an ancillary nuclear spin close to the NV center can be used to measure the
field perpendicular to the axis. Experimentally, both the Zeeman shift and
Larmor precession can be measured through the fluorescence from the NV center.
By applying additional calibrated magnetic fields, complete information of the
vector magnetic field can be achieved with such a method. This vector magnetic
field detection method is insensitive to temperature fluctuation and it can be
applied to nanoscale magnetic measurement.Comment: 5 pages, 5 figure
The Magnetic Properties of 1111-type Diluted Magnetic Semiconductor (LaBa)(ZnMn)AsO in the Low Doping Regime
We investigated the magnetic properties of
(LaBa)(ZnMn)AsO with varying from 0.005 to 0.05
at an external magnetic field of 1000 Oe. For doping levels of 0.01,
the system remains paramagnetic down to the lowest measurable temperature of 2
K. Only when the doping level increases to = 0.02 does the ferromagnetic
ordering appear. Our analysis indicates that antiferromagnetic exchange
interactions dominate for 0.01, as shown by the negative Weiss
temperature fitted from the magnetization data. The Weiss temperature becomes
positive, i.e., ferromagnetic coupling starts to dominate, for 0.02.
The Mn-Mn spin interaction parameter is estimated to be in
the order of 10 K for both 0.01 (antiferromagnetic ordered state)
and 0.02 (ferromagnetic ordered state). Our results unequivocally
demonstrate the competition between ferromagnetic and antiferromagnetic
exchange interactions in carrier-mediated ferromagnetic systems.Comment: 9 pages, 3 figure
Mesoscopic Kondo effect of a quantum dot embedded in an Aharonov-Bohm ring with intradot spin-flip scattering
We study the Kondo effect in a quantum dot embedded in a mesoscopic ring
taking into account intradot spin-flip scattering . Based on the finite-
slave-boson mean-field approach, we find that the Kondo peak in the density of
states is split into two peaks by this coherent spin-flip transition, which is
responsible for some interesting features of the Kondo-assisted persistent
current circulating the ring: (1) strong suppression and crossover to a sine
function form with increasing ; (2) appearance of a "hump" in the
-dependent behavior for odd parity. -induced reverse of the persistent
current direction is also observed for odd parity.Comment: 7 pages,6 figures, to be published by Europhys. Let
(Sr3La2O5)(Zn1-xMnx)2As2: A Bulk Form Diluted Magnetic Semiconductor isostructural to the "32522" Fe-based Superconductors
A new diluted magnetic semiconductor system, (Sr3La2O5)(Zn1-xMnx)2As2, has
been synthesized and characterized. 10% Mn substitution for Zn in bulk form
(Sr3La2O5)Zn2As2 results in a ferromagnetic ordering below Curie temperature,
TC ~ 40 K. (Sr3La2O5)(Zn1-xMnx)2As2 has a layered crystal structure identical
to that of 32522-type Fe based superconductors, and represents the fifth DMS
family that has a direct counterpart among the FeAs high temperature
superconductor families.Comment: Accepted for publication in EP
The suppression of Curie temperature by Sr doping in diluted ferromagnetic semiconductor (La1-xSrx)(Zn1-yMny)AsO
(La1-xSrx)(Zn1-yMny)AsO is a two dimensional diluted ferromagnetic
semiconductor that has the advantage of decoupled charge and spin doping. The
substitution of Sr2+ for La3+ and Mn2+ for Zn2+ into the parent semiconductor
LaZnAsO introduces hole carriers and spins, respectively. This advantage
enables us to investigate the influence of carrier doping on the ferromagnetic
ordered state through the control of Sr concentrations in
(La1-xSrx)(Zn0.9Mn0.1)AsO. 10 % Sr doping results in a ferromagnetic ordering
below TC ~ 30 K. Increasing Sr concentration up to 30 % heavily suppresses the
Curie temperature and saturation moments. Neutron scattering measurements
indicate that no structural transition occurs for (La0.9Sr0.1)(Zn0.9Mn0.1)AsO
below 300 K.Comment: Submitted to EP
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