Precise engineering of quantum states of matter and innovative laser technology are revolutionizing the performance of atomic clocks and metrology, providing new opportunities to explore emerging phenomena, test fundamental symmetry, and search for new physics. The recent work of measuring gravitational time dilation at the sub-millimeter scale highlights exciting prospects for new scientific discovery and technology development.

Single-photon subtraction (SPS) is useful for engineering optical quantum states and can be accomplished experimentally by heralding on the detection of one photon in the output port of a beamsplitter. Alternatively, conditioning on zero reflected photons modifies states by “zero-photon subtraction” (ZPS). Here we experimentally demonstrate that ZPS reduces the mean photon number of superpositions/mixtures of Fock states. The observed trends in attenuation show a dependence on the Mandel Q parameter for various input states, resulting in complementary behavior between SPS and ZPS. Theoretical results also show higher-order effects on the photon number distribution, beyond reduction in mean photon number.

We examine theoretically thermoelectric detector pixel design comprised of SiO2/ BSCCO/CeB6/ BSCCO/Al2O3 for 0.8 eV–1 keV photon energy range. We study heat transfer and show that our configuration is capable of providing a gigahertz count rate and high detection efficiency at the single-photon level at 9K. Then we examine the influence of possible noise channels and discuss pathways for creating a fast single-photon detector operating at LN temperatures.

Entanglement is a fundamental resource not only for quantum communication but also for distributed quantum computation. Especially, entanglement including only one type of error is favorable, compared with one including multiple types of noise. In this talk, we consider protocol that presents single-error-type entanglement for distant qubits via coherent-state transmission over lossy channels. This protocol is considered to be a subroutine to serve entanglement for larger protocol to yield a final output, such as ebits or pbits. A protocol based on remote non-destructive parity measurement (RNPM) [K. Azuma, H. Takeda, M. Koashi, and N. Imoto, Phys. Rev. A 85, 062309 (2012)] is identified as a subroutine which achieves the global optimal for typical yield functions monotonically non-decreasing with respect to the singlet fraction, such as an arbitrary convex function of a singlet fraction and two-way distillable entanglement/key.

Cold and ultracold states of matter have great potential to enable and disrupt applications of information science, sensing, navigation, and timekeeping. In this talk, we will explore several exciting topics within the cold atom quantum sensor space, including context for the specific challenges and relevant technologies that enable sensing applications on cold atom platforms. To successfully transition these states of matter from pure science to out-of-the-laboratory critical engineering tools, it is necessary to simplify, stabilize--and ultimately commercialize--the building blocks of cold atom systems. We present enabling technologies to address the technical challenges of preparing cold atom-based systems.

In this work, recent developments in the study of Superconducting Nanowire Single Photon Detectors (SNSPDs) are presented. This devices properties highly depends on the quality of the superconducting films from which they are fabricated. Here, we study some film properties for SNSPDs made out of NbTiN and MoSi in function of the deposition parameters. Subsequently we focus on the properties of the fabricated detector, such as efficiency, timing resolution and energy sensitivity.

This conference presentation was prepared for Quantum Communications and Quantum Imaging XX at SPIE Optical Engineering + Applications, 2022.

Collective qubits between atomic ground and Rydberg states can be converted, on-demand, into single photons, making them well-suited for scalable quantum network-type protocols. We demonstrate long-lived many-body Rabi oscillations and multi-particle entanglement, as well as study the dynamics of interaction-induced dephasing for collective Rydberg qubits held in a state-insensitive optical lattice trap. Both excitation blockade and spin-wave dephasing can contribute to suppression of multiple excitations, allowing for deterministic preparation of collective atomic qubits, single photons, and atom-photon entanglement for quantum information processing.

The quantum internet will give us an infrastructure able to distribute and process quantum information on a planetary scale. The core of that internet will be formed from quantum error corrected links able to distribute information over large distances all while maintaining their coherence for long periods of time. However, many of the applications at the edge of such networks may rely on raw unencoded data – not protected by error correcting codes due to the nature of how it was generated. In this presentation, we will describe an experiment in which quantum information encoded on a physical qubit can be teleported into an error-corrected logical qubit. Our demonstration shows how one can get information into and out of quantum processors and tomorrows large-scale quantum networks.

Nowadays, a technological challenge is to integrate quantum key distribution (QKD) protocols in already present telecommunication fiber networks. Twin-field QKD is one of the most promising techniques on long distances, but requires stabilizing the optical length of the communication channels between parties. Adapting interferometry techniques derived from frequency metrology, we developed a solution for the simultaneous key sharing and channel length control, and we demonstrated it on a 206 km field-deployed fiber with 65 dB loss. Our method reduces the quantum-bit-error-rate contributed by channel length variations to <1%, representing an effective solution for real-world quantum communications.