Y. J. Sun

Perspectives of a mid-rapidity dimuon program at the RHIC: a novel and compact muon telescope detector

Perspectives of a mid-rapidity dimuon program at the RHIC: a novel and compact muon telescope detector L Ruan 1 , G Lin 2 , Z Xu 1 , K Asselta 1 , H F Chen 3 , W Christie 1 , H J Crawford 4 , J Engelage 4 , G Eppley 5 , T J Hallman 1 , C Li 3 , J Liu 5 , W J Llope 5 , R Majka 2 , T Nussbaum 5 , J Scheblein 1 , M Shao 3 , R Soja 1 , Y Sun 3 , Z Tang 3 , X Wang 6 and Y Wang 6 July 17, 2009 This work was supported by the Director, Office of Science, Office of Nuclear Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.

Storage of multiple single-photon pulses emitted from a quantum dot in a solid-state quantum memory

Quantum repeaters are critical components for distributing entanglement over long distances in presence of unavoidable optical losses during transmission. Stimulated by the Duan–Lukin–Cirac–Zoller protocol, many improved quantum repeater protocols based on quantum memories have been proposed, which commonly focus on the entanglement-distribution rate. Among these protocols, the elimination of multiple photons (or multiple photon-pairs) and the use of multimode quantum memory are demonstrated to have the ability to greatly improve the entanglement-distribution rate. Here, we demonstrate the storage of deterministic single photons emitted from a quantum dot in a polarization-maintaining solid-state quantum memory; in addition, multi-temporal-mode memory with 1, 20 and 100 narrow single-photon pulses is also demonstrated. Multi-photons are eliminated, and only one photon at most is contained in each pulse. Moreover, the solid-state properties of both sub-systems make this configuration more stable and easier to be scalable. Our work will be helpful in the construction of efficient quantum repeaters based on all-solid-state devices.

Calibration and performance of the STAR Muon Telescope Detector using cosmic rays

We report the timing and spatial resolution from the Muon Telescope Detector (MTD) installed in the STAR experiment at RHIC. Cosmic ray muons traversing the STAR detector have an average transverse momentum of 6 GeV/c. Due to their very small multiple scattering, these cosmic muons provide an ideal tool to calibrate the detectors and measure their timing and spatial resolution. The values obtained were ∼100 ps and ∼1-2 cm, respectively. These values are comparable to those obtained from cosmic-ray bench tests and test beams.

Test of high time resolution MRPC with different readout modes for the BESIII upgrade

In order to further enhance the particle identification capability of the Beijing Spectrometer (BESIII), it is proposed to upgrade the current end-cap time-of-flight (eTOF) detector with multi-gap resistive plate chamber (MRPC). The prototypes, together with the front end electronics (FEE) and time digitizer (TDIG) module have been tested at the E3 line of Beijing Electron Positron Collider (BEPCII) to study the difference between the single and double-end readout MRPC designs. The time resolutions (sigma) of the single-end readout MRPC are 47/53 ps obtained by 600 MeV/c proton/pion beam, while that of the double-end readout MRPC is 40 Ps (proton beam). The efficiencies of three MRPC modules tested by both proton and pion beam are better than 98%. For the double-end readout MRPC, no incident position dependence is observed

First results of the new endcap TOF commissioning at BESIII

The upgrade of the current BESIII Endcap TOF (ETOF) is carried out with Multi-gap Resistive Plate Chamber (MRPC) technology. The installation of the new ETOF has been finished in October 2015. The first results of the MRPCs commissioning at BESIII are reported in this paper.

Heisenberg-scaling measurement of the single-photon Kerr non-linearity using mixed states

Improving the precision of measurements is a significant scientific challenge. Previous works suggest that in a photon-coupling scenario the quantum fisher information shows a quantum-enhanced scaling of N2, which in theory allows a better-than-classical scaling in practical measurements. In this work, utilizing mixed states with a large uncertainty and a post-selection of an additional pure system, we present a scheme to extract this amount of quantum fisher information and experimentally attain a practical Heisenberg scaling. We performed a measurement of a single-photon’s Kerr non-linearity with a Heisenberg scaling, where an ultra-small Kerr phase of ≃6 × 10−8 rad was observed with a precision of ≃3.6 × 10−10 rad. From the use of mixed states, the upper bound of quantum fisher information is improved to 2N2. Moreover, by using an imaginary weak-value the scheme is robust to noise originating from the self-phase modulation.Quantum metrology usually relies on entanglement or squeezing for pursuing Heisenberg-limited precision. In this work, instead, the authors demonstrate Heisenberg-scaling measurement of a single photon Kerr’s nonlinearity using less-demanding mixed states.

The CBM Time-of-Flight wall — a conceptual design

Charged hadron identification in the Compressed Baryonic Matter experiment (CBM) is realized via the Time-of-Flight method [1]. For this purpose the CBM-ToF collaboration designed a Time-of-Flight wall composed of Multi-gap Resistive Plate Chambers (MRPCs). Due to the high interaction rate in CBM of 10 MHz the key challenge is the development of high rate MRPCs above 25 kHz/cm2 which become possible after the development of low resistive glass with extremely good quality. In this article we present the actual conceptual design of the ToF-wall which is subdivided in three parts namely the outer wall, the inner wall and the forward zone that are discussed in detail.

MRPC detector for the BESIII E-TOF upgrade

An end-cap Time-of-Flight (E-TOF) system with higher granularity compare to the current E-TOF and intrinsic time resolution of better than 50 ps will extend the K/pi separation (2 sigma) momentum range to 1.4 GeV/c and enhance the physics capability of Beijing Spectrometer (BESIII). A R&D project was carried out aiming at upgrading the current BESIII E-TOF with the Multi-gap Resistive Plate Chamber (MRPC). The beam test for the MRPC prototype, together with the custom-designed Front End Electronics (FEE) and TDC boards, was performed at the BEPC E3 line in the last years. The test results show that the detector has stable performance at different positions and working High Voltage (HV). A time resolution of better than 50 ps can be achieved. The different performance between pion and proton events is also discussed.

Measurement of the inhomogeneous broadening of a bi-exciton state in a quantum dot using Franson-type nonlocal interference

The inhomogeneous broadening of the bi-exciton state in quantum dots, i.e., the inhomogeneous broadening of the upper level of the cascade process, is not only a fundamental problem in quantum dots, but also closely related with the coherent control of this complex system and the quality of the entangled photon pairs, especially the time-bin entangled photon pairs. This inhomogeneous broadening is inherently a two-photon correlated phenomenon. In this work, we construct a genuine Franson-type nonlocal interference process to measure the inhomogeneous broadening of the bi-exciton state. The results show that the inhomogeneous broadening of the bi-exciton state is considerably smaller than that of the exciton state, that is why the entangled photon pairs can be generated by the cascade process in the quantum dot.

Multi-peak pattern in Multi-gap RPC time-over-threshold distributions and an offline calibration method

The Beijing Spectrometer (BESIII) has just updated its end-cap Time-of-Flight (ETOF) system, using the Multi-gap Resistive Plate Chamber (MRPC) to replace the current scintillator detectors. These MRPCs shows multi-peak phenomena in their time-over-threshold (TOT) distribution, which was also observed in the Long-strip MRPC built for the RHIC-STAR Muon Telescope Detector (MTD). After carefully investigated the correlation between the multi-peak distribution and incident hit positions along the strips, we find out that it can be semi-quantitatively explained by the signal reflections on the ends of the readout strips. Therefore a new offline calibration method was implemented on the MRPC ETOF data in BESIII, making T-TOT correlation significantly improved to evaluate the time resolution.