722 research outputs found
Heralded quantum steering over a high-loss channel
Entanglement is the key resource for many long-range quantum information
tasks, including secure communication and fundamental tests of quantum physics.
These tasks require robust verification of shared entanglement, but performing
it over long distances is presently technologically intractable because the
loss through an optical fiber or free-space channel opens up a detection
loophole. We design and experimentally demonstrate a scheme that verifies
entanglement in the presence of at least dB of added loss,
equivalent to approximately km of telecommunication fiber. Our protocol
relies on entanglement swapping to herald the presence of a photon after the
lossy channel, enabling event-ready implementation of quantum steering. This
result overcomes the key barrier in device-independent communication under
realistic high-loss scenarios and in the realization of a quantum repeater.Comment: 8 pages, 5 figure
ΠΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½ΠΈΠ΅ IoT-ΡΠ΅Ρ Π½ΠΎΠ»ΠΎΠ³ΠΈΠΉ Π² Π·Π°ΡΠΈΡΠ΅ ΠΎΠΊΡΡΠΆΠ°ΡΡΠ΅ΠΉ ΡΡΠ΅Π΄Ρ
ΠΠΎΠ»ΡΡΠΈΠ½ΡΡΠ²ΠΎ Π΄ΠΈΡΠΊΡΡΡΠΈΠΉ Π²ΠΎΠΊΡΡΠ³ ΡΠ΅Π½ΠΎΠΌΠ΅Π½Π° ΠΠ½ΡΠ΅ΡΠ½Π΅ΡΠ° Π²Π΅ΡΠ΅ΠΉ (IoT) ΠΎΠ±ΡΡΠ½ΠΎ ΡΠ²ΠΎΠ΄ΠΈΡΡΡ ΠΊ ΡΠ΅ΠΌ ΠΏΠΎΡΠ΅Π½ΡΠΈΠ°Π»ΡΠ½ΡΠΌ ΠΏΡΠ΅ΠΈΠΌΡΡΠ΅ΡΡΠ²Π°ΠΌ Π΄Π»Ρ Π±ΠΈΠ·Π½Π΅ΡΠ° ΠΈ ΠΊ ΡΠ΅ΠΌ ΡΠ΄ΠΎΠ±ΡΡΠ²Π°ΠΌ Π΄Π»Ρ ΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°ΡΠ΅Π»Π΅ΠΉ, ΠΊΠΎΡΠΎΡΡΠ΅ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°ΡΡ ΠΈΠ½ΡΠ΅Π»Π»Π΅ΠΊΡΡΠ°Π»ΡΠ½ΡΠ΅ ΡΡΡΡΠΎΠΉΡΡΠ²Π° ΠΈ ΠΎΠ±ΡΠ΅ΠΊΡΡ, ΠΎΠΊΡΡΠΆΠ°ΡΡΠΈΠ΅ Π½Π°Ρ Π΅ΠΆΠ΅Π΄Π½Π΅Π²Π½ΠΎ. ΠΠ΄Π½Π°ΠΊΠΎ, ΠΊΠ°ΠΊΠΈΠΌ ΠΎΠ±ΡΠ°Π·ΠΎΠΌ ΠΠ½ΡΠ΅ΡΠ½Π΅Ρ Π²Π΅ΡΠ΅ΠΉ ΠΈ ΠΈΠ½Π΄ΡΡΡΡΠΈΠ°Π»ΡΠ½ΡΠΉ ΠΠ½ΡΠ΅ΡΠ½Π΅Ρ Π²Π΅ΡΠ΅ΠΉ (M2M - machine-to-machine), ΡΠΎ Π΅ΡΡΡ Π±Π΅ΡΠΏΡΠΎΠ²ΠΎΠ΄Π½Π°Ρ ΠΏΠ΅ΡΠ΅Π΄Π°ΡΠ° Π΄Π°Π½Π½ΡΡ
ΠΈ ΠΈΠ½ΡΠΎΡΠΌΠ°ΡΠΈΠΈ ΠΌΠ΅ΠΆΠ΄Ρ ΡΡΡΡΠΎΠΉΡΡΠ²Π°ΠΌΠΈ ΠΈ ΠΎΠ±ΡΠ΅ΠΊΡΠ°ΠΌΠΈ, Π±ΡΠ΄Π΅Ρ ΡΠΏΠΎΡΠΎΠ±ΡΡΠ²ΠΎΠ²Π°ΡΡ ΡΡΡΠΎΠΉΡΠΈΠ²ΠΎΠΌΡ ΡΠ°Π·Π²ΠΈΡΠΈΡ ΠΈ Π·Π°ΡΠΈΡΠ΅ ΠΎΠΊΡΡΠΆΠ°ΡΡΠ΅ΠΉ ΡΡΠ΅Π΄Ρ.Most of the discussions around the phenomenon of the Internet of Things (IoT) usually boils down to those potential benefits for the business and to those amenities for users that provide intelligent devices and objects that surround us daily. However, how the Internet of things and the industrial Internet of things (M2M - machine-to-machine), that is, the wireless transmission of data and information between devices and objects, can have a beneficial effect on our lives and will contribute to sustainable development and the protection of the environment on the planet
Development of the heat and mass transfer model for the study of the temperature traces water droplets in a flame
The heat and mass transfer model is developed with using Ansys Fluent. The typical temperature of gases in the trace of water droplets is determined (initial temperature of gases 1170 Π). Several types for the location of water droplets are studied: two successive water droplets; two parallel water droplets; five water droplets in checkerboard order. The hypothesis about gas temperature reduction in the trace of a moving liquid is confirmed
Measured and simulated heavy-ion beam loss patterns at the CERN Large Hadron Collider
The Large Hadron Collider (LHC) at CERN pushes forward to new regimes in terms of beam energy and intensity. In view of the combination of very energetic and intense beams together with sensitive machine components, in particular the superconducting magnets, the LHC is equipped with a collimation system to provide protection and intercept uncontrolled beam losses. Beam losses could cause a superconducting magnet to quench, or in the worst case, damage the hardware. The collimation system, which is optimized to provide a good protection with proton beams, has shown a cleaning efficiency with heavy-ion beams which is worse by up to two orders of magnitude. The reason for this reduced cleaning efficiency is the fragmentation of heavy-ion beams into isotopes with a different mass to charge ratios because of the interaction with the collimator material. In order to ensure sufficient collimation performance in future ion runs, a detailed theoretical understanding of ion collimation is needed. The simulation of heavy-ion collimation must include processes in which Pb82+208 ions fragment into dozens of new isotopes. The ions and their fragments must be tracked inside the magnetic lattice of the LHC to determine their loss positions. This paper gives an overview of physical processes important for the description of heavy-ion loss patterns. Loss maps simulated by means of the two tools ICOSIM [1,2] and the newly developed STIER (SixTrack with Ion-Equivalent Rigidities) are compared with experimental data measured during LHC operation. The comparison shows that the tool STIER is in better agreement.peer-reviewe
Acoustic metamaterial capsule for reduction of stage machinery noise
Noise mitigation of stage machinery can be quite demanding and requires innovative solutions. In this work we propose an acoustic metamaterial capsule to reduce the noise emission of several stage machinery drive trains, while still allowing the ventilation required for cooling. The metamaterial capsule consists of c-shape meta atoms, which have a simple structure that facilitates manufacturing. We design, simulate, manufacture, and experimentally validate two different metamaterial capsules, which utilize an ultra-sparse and air-permeable reflective meta-grating. Both designs demonstrate transmission loss peaks that effectively suppress gear mesh noise or other narrow band noise sources. The ventilation by natural convection was numerically verified, and was shown to give adequate cooling, whereas a conventional sound capsule would lead to overheating. The noise spectra of three common stage machinery drive trains are numerically modelled, enabling us to design meta-gratings and determine their noise suppression performance. The results fulfill the stringent stage machinery noise limits, highlighting the benefit of using metamaterial capsule of simple c-shape structure
ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΈ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠ° Π³ΠΈΡΡΠ΅ΡΠ΅Π·ΠΈΡΠ½ΡΡ ΡΠ»Π΅ΠΊΡΡΠΈΡΠ΅ΡΠΊΠΈΡ ΠΌΠ°ΡΠΈΠ½ Π½Π° ΠΎΡΠ½ΠΎΠ²Π΅ Π΄Π΅ΡΠΎΡΠΌΠΈΡΡΠ΅ΠΌΠΎΠ³ΠΎ ΡΠΏΠ»Π°Π²Π° Fe-Cr-Co
Π Ρ
ΠΎΠ΄Π΅ Π½Π°ΡΡΠ½ΠΎ-ΠΊΠ²Π°Π»ΠΈΡΠΈΠΊΠ°ΡΠΈΠΎΠ½Π½ΠΎΠΉ ΡΠ°Π±ΠΎΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π» ΡΠΎΡΠΎΡΠ° ΡΠΈΠ½Ρ
ΡΠΎΠ½Π½ΠΎΠ³ΠΎ Π³ΠΈΡΡΠ΅ΡΠ΅Π·ΠΈΡΠ½ΠΎΠ³ΠΎ Π΄Π²ΠΈΠ³Π°ΡΠ΅Π»Ρ (Π‘ΠΠ) ΠΈΠ· ΡΠΏΠ»Π°Π²Π° 22Π₯15ΠΠ ΠΠΠ‘Π’ 24897-81. ΠΠΎΠ»ΡΡΠ΅Π½Ρ Π΄ΠΈΠ½Π°ΠΌΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΌΠ°Π³Π½ΠΈΡΠ½ΡΠ΅ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠΈ ΡΠΏΠ»Π°Π²Π° Π½Π° ΡΠ°ΡΡΠΎΡΠ°Ρ
ΠΏΠ΅ΡΠ΅ΠΌΠ°Π³Π½ΠΈΡΠΈΠ²Π°Π½ΠΈΡ ΠΎΡ 50 ΠΡ Π΄ΠΎ 2 ΠΊΠΡ. ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ Π‘ΠΠ Π² ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ½ΠΎΠΉ ΡΡΠ΅Π΄Π΅ AnsysMaxwell 2D/3D.In the course of the scientific and qualifying work, the rotor material of the synchronous hysteresis motor from alloy 22Π₯15ΠΠ GOST 24897-81 was investigated. Dynamic magnetic characteristics of the alloy at the magnetization reversal frequencies from 50 Hz to 2 kHz are obtained. The results of the study of a synchronous hysteresis motor in the software environment of AnsysMaxwell 2D / 3D are presented
Generation of x-ray radiation in a storage ring by a superconductive cold-bore invacuum undulator
The first beam measurements with a cold-bore superconducting in-vacuum undulator in a storage ring are reported. Undulators are x-ray generators in light sources. The physical limitations of these devices limit the intensity and the brilliance of the x-ray beam. At present the undulators are made from permanent magnets. It was shown in earlier papers that at low electron beam intensities superconductive wires in the vacuum beam pipe can overcome the limitations inherent to permanent magnet undulators. It was argued that the use of these novel devices in light sources with high beam currents may be limited by the extreme anomalous skin effect regime in Cu at 4.2 K, which has so far undergone very little investigation, and the power deposited by the infrared part of the synchrotron radiation. The purpose of this paper is to present measurements of these effects at the synchrotron light source ANKA with stored currents up to 200 mA
Multi-turn losses and cleaning
In the LHC all multi-turn losses should occur at the collimators in the cleaning insertions. The cleaning inefficiency
(leakage rate) is the figure of merit to describe the performance. In combination with the quench limit of the superconducting magnets and the instantaneous life time of
the beam this defines the cleaning dependent beam intensity limit of the LHC. In addition, limits can arise from
radiation-induced effects, like radiation damage and radation to electronics. In this paper the used collimator settings, the required setup time, the reliability of collimation
(all multi-turn losses at collimators), and the achieved proton/ion cleaning inefficiency are discussed. Observed and
expected losses are compared. The performance evolution
during the months of operation is reviewed. In addition,
the peak losses during high intensity runs, losses caused
by instabilities, and the resulting beam life times are discussed. Taking the observations into account the intensity
reach with collimation at 3.5 and 4 TeV is reviewed.peer-reviewe
Testing Beam-Induced Quench Levels of LHC Superconducting Magnets
In the years 2009-2013 the Large Hadron Collider (LHC) has been operated with
the top beam energies of 3.5 TeV and 4 TeV per proton (from 2012) instead of
the nominal 7 TeV. The currents in the superconducting magnets were reduced
accordingly. To date only seventeen beam-induced quenches have occurred; eight
of them during specially designed quench tests, the others during injection.
There has not been a single beam- induced quench during normal collider
operation with stored beam. The conditions, however, are expected to become
much more challenging after the long LHC shutdown. The magnets will be
operating at near nominal currents, and in the presence of high energy and high
intensity beams with a stored energy of up to 362 MJ per beam. In this paper we
summarize our efforts to understand the quench levels of LHC superconducting
magnets. We describe beam-loss events and dedicated experiments with beam, as
well as the simulation methods used to reproduce the observable signals. The
simulated energy deposition in the coils is compared to the quench levels
predicted by electro-thermal models, thus allowing to validate and improve the
models which are used to set beam-dump thresholds on beam-loss monitors for Run
2.Comment: 19 page
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