# QIRG Seminar: Mehdi Namazi / Qunnect

*Blue sheets are at the bottom*

[Datatracker event](https://datatracker.ietf.org/doc/agenda-interim-2021-qirg-01-qirg-01/)

**Abstract:** Long-distance quantum entanglement distribution is a revolutionary idea that aims to harness quantum physics's power to enhance the way we transfer information. A real implementation of these networks will have applications from ultra-secure networking and distributed quantum computing to the unprecedented sensitivity of distributed quantum sensor networks. Though the promise is unique, we are still years away from a real-world, large-scale quantum network that would allow multiple quantum devices to work together efficiently, outside the laboratory space and plugged into the current telecommunication infrastructure. Qunnect's mission is to address the hardware challenges of realizing telecom integrated quantum networks, one module at a time while ensuring scalability. Throughout this talk, we will discuss Qunnect's room-temperature approach to quantum memories, quantum repeaters, and the challenges that lay ahead to accelerate long-distance quantum networks' growth.

**Speaker bio:** Mehdi is the cofounder and Chief Science Officer of Qunnect Inc. He graduated with his Ph.D. in AMO Physics at SBU's Quantum Information Processing & Technology laboratory in 2018. During his Ph.D., Mehdi worked on several aspects of quantum communication technologies. Most notably, he realized the first unconditional room-temperature quantum memory, securely storing information and performing quantum key distribution protocols and simulating relativistic quantum particles using light-matter interactions. In 2018, Mehdi was awarded the Yale Joint Quantum Institute Postdoctoral Fellowship to work on novel quantum optomechanical systems that would allow for ultra-precise measurement of fundamental constants. He served as the CEO of Qunnect during the initial years and eventually transitioned to the Chief Science Officer in 2020.

**Company bio:** Qunnect is building a scalable product suite to upgrade and enhance telecommunications infrastructure with quantum capabilities. URL: http://www.qunnect.inc/

## Q&A Minutes

* Olaf: So the phonto's state is preserved as it is absorbed?
  * Rod: Yes. this is popular in the press as "stopped light". You create some some of state of the atoms that allows you to cause emission of a (theoretically) identical photon at some later time.

* Kian: why you need a memory in the scheme of swapping entanglement. Is it to bridge the asymmetry of timing of creating entangled states from different pairs?
  * Mehdi: To avoid relying on the simultaneous success of all BSMs in the network.

* Bruno: what end-to-end network performance have you achieved in actual devices (entanglements per second, fidelity, distance)?
    * Mehdi: Research is ongoing since 2013, but we are in a new lab last august so not everything is back up to speed. 5-10 kHz or 18 kHz are typical for entanglement sources, but we hope to bring them up to MHz. Hard to say what is the end-to-end performance. Limiting factor really is the time to wait for a successful swap + time to know about it (signal from the heralding station). But as long as it's better than direct fiber then it's an engineering problem.

* Patrick: Is it envisaged that the quantum memory is compatible with the telecom frequencies 1550 nm?
    * Mael:  Rb has transitions in a wide range of wavelengths. Currently we've confirmed opperation for 780/795nm (freespace) and 1324/1367nm (fiber). Rb does have a transition in the 15xxnm range however using 13xxnm for the quantum signals permits to have a co-propagating classical control layer at 1550nm.

* Chonggang:  Wonder what's the current maturity of quantum measurement including BSM or other types of q-measurements, for example, in terms of accuracy, hardware complexity and availability/cost, etc.?
    * Mehdi: We cannot use conventional photon counters which makes it very expensive (price is mostly in the detectors). Once rates increase perhaps cheaper detectors can be used. BSMs are complicated due to indistinguishability of photons and timing. Achieving these conditions in a lab is much easier, not so much outside of a lab. Expect BSM efficiency ~10%.

* Kian: Are these generation rates before or after the filtering you have to do? (if I understand correctly you need this still?) Or maybe better question - what is your expectance entangling rate?
    * Mehdi: Rates will always be affected by many factors. Expected rates are low. Expected rate is low (10^-2 per second) without any multiplexing. Limited by how much time it takes the photons to arrive at BSMs.

* Kian: surrounding hardware you need to build. How mature do you see this and at what level is it and what effort will need to be put into it in the future?
    * Mehdi: We are developing 7 devices. Understanding of networking is actually limited so need field testing to learn about timings and polarization compensation. Hoping to get out alpha/beta ready by the end of the year.