اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدA Compact PCI-based Measurement and Control System for Satellite-Ground Quantum Communication
84
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Since the 1990s, there has been a dramatic interest in quantum communication. Free-space quantum communication is being developed to ultra-long distance quantum experiment, which requires higher electronics performance, such as time measurement precision, data-transfer rate, and system integration density. As part of the ground station of quantum experiment satellite that will be launched in 2016, we specifically designed a compact PCI-based multi-channel electronics system with high time-resolution, high data-transfer-rate. The electronics performance of this system was tested. The time bin size is 23.9ps and the time precision root-mean-square (RMS) is less than 24ps for 16 channels. The dead time is 30ns. The data transfer rate to local computer is up to 35 MBps, and the count rate is up to 30M/s. The system has been proven to perform well and operate stably through a test of free space quantum key distribution (QKD) experiment.
قيم البحث
اقرأ أيضاً
We build and test a single-photon detector based on a Si avalanche photodiode Excelitas 30902SH thermoelectrically cooled to -100 deg. C. Our detector has dark count rate below 1 Hz, 500 um diameter photosensitive area, photon detection efficiency ar
ound 50%, afterpulsing less than 0.35%, and timing jitter under 1 ns. These characteristics make it suitable for long-distance free-space quantum communication links, which we briefly discuss. We also report an improved method that we call long-time afterpulsing analysis, used to determine and visualise long trap lifetimes at different temperatures.
We develop a polarization characterization platform for optical devices in free-space quantum communications. We demonstrate an imaging polarimeter, which analyzes both incident polarization states and the angle of incidence, attached to a six-axis c
ollaborative robot arm, enabling polarization characterization at any position and direction with consistent precision. We present a detailed description of each subsystem including the calibration and polarization-test procedure, and analyze polarization-measurement errors caused by imperfect orientations of the robot arm using a Mueller-matrix model of polarimeters at tilt incidence. We perform a proof-of-principle experiment for an angle-dependent polarization test for a commercial silver-coated mirror for which the polarization states of the reflected light can be accurately calculated. Quantitative agreement between the theory and experiment validates our methodology. We demonstrate the polarization test for a 20.3 cm lens designed for a quantum optical transmitter in Canadas Quantum Encryption and Science Satellite (QEYSSat) mission.
As quantum information processors grow in quantum bit (qubit) count and functionality, the control and measurement system becomes a limiting factor to large scale extensibility. To tackle this challenge and keep pace with rapidly evolving classical c
ontrol requirements, full control stack access is essential to system level optimization. We design a modular FPGA (field-programmable gate array) based system called QubiC to control and measure a superconducting quantum processing unit. The system includes room temperature electronics hardware, FPGA gateware, and engineering software. A prototype hardware module is assembled from several commercial off-the-shelf evaluation boards and in-house developed circuit boards. Gateware and software are designed to implement basic qubit control and measurement protocols. System functionality and performance are demonstrated by performing qubit chip characterization, gate optimization, and randomized benchmarking sequences on a superconducting quantum processor operating at the Advanced Quantum Testbed at Lawrence Berkeley National Laboratory. The single-qubit and two-qubit process fidelities are measured to be 0.9980$pm$0.0001 and 0.948$pm$0.004 by randomized benchmarking. With fast circuit sequence loading capability, the QubiC performs randomized compiling experiments efficiently and improves the feasibility of executing more complex algorithms.
Recent rapid growth in the number of satellite-constellation programs for remote sensing and communications, thanks to the availability of small-size and low-cost satellites, provides impetus for high capacity laser communication (lasercom) in space.
Quantum communication can enhance the overall performance of lasercom, and also enables intrinsically hack-proof secure communication known as Quantum Key Distribution (QKD). Here, we report a quantum communication experiment between a micro-satellite (48 kg and 50 cm cube) in a low earth orbit and a ground station with single-photon counters. Non-orthogonal polarization states were transmitted from the satellite at a 10-MHz repetition rate. On the ground, by post-processing the received quantum states at an average of 0.14 photons/pulse, clock data recovery and polarization reference-frame synchronization were successfully done even under remarkable Doppler shifts. A quantum bit error rate below 5% was measured, demonstrating the feasibility of quantum communication in a real scenario from space.
An arbitrary unknown quantum state cannot be precisely measured or perfectly replicated. However, quantum teleportation allows faithful transfer of unknown quantum states from one object to another over long distance, without physical travelling of t
he object itself. Long-distance teleportation has been recognized as a fundamental element in protocols such as large-scale quantum networks and distributed quantum computation. However, the previous teleportation experiments between distant locations were limited to a distance on the order of 100 kilometers, due to photon loss in optical fibres or terrestrial free-space channels. An outstanding open challenge for a global-scale quantum internet is to significantly extend the range for teleportation. A promising solution to this problem is exploiting satellite platform and space-based link, which can conveniently connect two remote points on the Earth with greatly reduced channel loss because most of the photons propagation path is in empty space. Here, we report the first quantum teleportation of independent single-photon qubits from a ground observatory to a low Earth orbit satellite - through an up-link channel - with a distance up to 1400 km. To optimize the link efficiency and overcome the atmospheric turbulence in the up-link, a series of techniques are developed, including a compact ultra-bright source of multi-photon entanglement, narrow beam divergence, high-bandwidth and high-accuracy acquiring, pointing, and tracking (APT). We demonstrate successful quantum teleportation for six input states in mutually unbiased bases with an average fidelity of 0.80+/-0.01, well above the classical limit. This work establishes the first ground-to-satellite up-link for faithful and ultra-long-distance quantum teleportation, an essential step toward global-scale quantum internet.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
