Program
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LSU SQuInT Event Map
SESSION 13: Quantum light and matter experiments (Theatre)Chair: (Poul Jessen (Arizona)) | |
| 3:15pm - 3:45pm | Ioana Craiciu, IQIM, Caltech Quantum light matter interfaces using erbium doped yttrium orthosilicate | Abstract. Rare earth quantum light-matter interfaces (QLMIs), consisting of optical resonators coupled to ensembles of rare earth ions, are uniquely suited for various quantum information applications, including quantum memories and quantum optical-to-microwave transducers. Among rare earths, erbium is particularly appealing due to its highly coherent resonance within a telecom band, allowing integration with existing optical communication technology and infrastructure. Micro-resonator QLMIs have various advantages over bulk rare earth crystals. They permit on-chip integration with other elements, such as microwave resonators for optical-to-microwave conversion. In the context of quantum memories, they provide enhanced coupling to the ions, and when the resonator is impedance matched to the ions, they can raise the theoretical memory efficiency to 100%. For spectral hole-burning based quantum memories, the coupling of rare earth ions to the resonator can provide improved memory initialization via Purcell enhancement of optical lifetimes. We present nano scale quantum light matter interfaces in erbium doped yttrium orthosilicate (Er:YSO). Our two types of devices take the form of nanobeam photonic crystal resonators milled directly into Er:YSO and of amorphous silicon ring resonators on Er:YSO. This latter hybrid design represents our newest efforts in a scalable on chip QLMI architecture. We have fabricated ring resonators with measured quality factors of over 10^5, and evanescent coupling to an ensemble of erbium ions characterized by a cooperativity of 0.54. The nanobeam resonator design has a measured quality factor of around 25,000, and a cooperativity of 2.4. We present simulation and experimental results of the optical properties of these cavities, and their coupling to erbium ions, including a demonstration of Purcell enhancement of the erbium telecom transition. We then analyze their potential as quantum memories. |
| 3:45pm - 4:15pm | Andrew Ferdinand, CQuIC, New Mexico Four wave mixing in a cold atomic ensemble for the generation of correlated photons pairs | Abstract. Photon pairs generated by spontaneous four-wave mixing (FWM) in atomic ensembles provide a natural path toward quantum light-matter interfaces due to their intrinsic compatibility with atomic quantum memories. These photons are narrow band and have frequencies at or close to atomic resonances, and their temporal and spectral properties can be efficiently tailored to make them compatible with specific quantum memory protocols [1]. In addition, conservation of orbital angular momentum (OAM) in the FWM process enables the generated photons to form entangled qudits, which have applications in high-dimensional quantum information and communication. We study experimentally the generation of light from FWM in a cold ensemble of cesium atoms. We investigate theoretically the correlation and distribution of OAM modes occupied by photon pairs produced in spontaneous FWM as a function of experimentally accessible parameters of the process. These studies provide the basis for future investigations of photonic OAM correlation generated with FWM in atomic ensembles. [1] Du et al., Phys. Rev. Lett. 100, 183603. (2008) |
| 4:15pm - 4:45pm | Tian Zhong, IQIM, Caltech A nanophotonic platform integrating quantum memories and single qubits based on rare-earth ions | Abstract. The integration of rare-earth ions in an on-chip photonic platform would enable quantum repeaters and scalable quantum networks. Here we demonstrate a nanophotonic platform consisting of yttrium vanadate (YVO) photonic crystal nanobeam resonators coupled to a spectrally dilute ensemble of Nd ions. The cavity acts as a memory when prepared with spectral hole burning, meanwhile it permits addressing of single ions. For quantum memory, atomic frequency comb (AFC) protocol was implemented in a Nd:YVO nanocavity cooled to 475 mk. We measure an efficiency at 2% at a storage time of ~100 ns with an efficient WSi superconducting nanowire detector (SNSPD). The small mode volume of the cavity results in a peak atomic spectral density of <10 ions per homogeneous linewidth, suitable for probing single ions when detuned. The high-cooperativity coupling of a single ion yields a strong signature (20%) in the cavity reflection spectrum. We estimate a signal-to-noise ratio exceeding 10 for addressing a single Nd ion. This, combines with the AFC memory, constitutes a promising platform for preparation, storage and detection of rare-earth qubits on the same chip. |
| 4:45pm - 5:15pm | Clemens Matthiesen, UC Berkeley, Cambridge Phase-tuned entangled state generation between distant spin qubits | Abstract. Entanglement is the central resource in quantum information processing, sensing and communication. Distribution of entanglement through non-local interactions, using photon interference and detection, is an attractive feature of flexible computation architectures where spatially separate nodes are locally controlled and connected via photonic channels. I will present very recent work from the Atatüre group in Cambridge on the generation of controllable entangled states between two electron spins confined in optically active indium-gallium-arsenide (InGaAs) quantum dots (QD) situated metres apart. The combination of a minimal single-photon state-projection scheme and the strong coherent light-matter interaction in these systems enables a distant entanglement rate of 7.3 kHz, the highest reported to date. With full control over the single-photon interference, we demonstrate the creation of entangled states with arbitrary phase. In the outlook I will discuss some limiting features of this semiconductor system [1], and highlight alternative venues for electron spin qubits trapped in vacuum [2]. [1] R. Stockill et al., Nature Comms 7, 12745 (2016). [2] P. Peng, C. Matthiesen, H Häffner, arXiv:1611.00130 [quant-ph] (2016). |
SQuInT Chief Organizer
Akimasa Miyake, Assistant Professor
amiyake@unm.edu
SQuInT Co-Organizer
Mark M. Wilde, Assistant Professor LSU
mwilde@phys.lsu.edu
SQuInT Administrator
Gloria Cordova
gjcordo1@unm.edu
505 277-1850
SQuInT Event Coordinator
Karen Jones, LSU
kjones@cct.lsu.edu
SQuInT Founder
Ivan Deutsch, Regents' Professor
ideutsch@unm.edu
