Upcoming Talks

Quantum systems that are highly controllable, scalable, and preserve quantum properties for extended periods of time are the key driver of the second quantum revolution. Atoms and molecules - pristine miniature quantum systems provided by Nature – have extremely promising properties in this regard. In this talk, I will discuss our recent progress in synthesizing, controlling, and stabilizing dipolar molecules of NaCs [1,2]. We have demonstrated that rotational qubits in NaCs can be controlled via microwave pulses on the nanosecond-scale, rivaling control times of many traditional qubit platforms. In addition, we have demonstrated that microwave shielding can enhance the lifetimes of dense NaCs ensembles by a factor of 100. NaCs molecules hold great promise for becoming a new modality for quantum simulation and quantum computing. I will also discuss our TweeSr project on optical tweezer arrays of strontium. We have developed a new source for cold strontium [4] and demonstrated holographic metasurfaces as a new way to create high-quality atomic tweezer arrays [5]. Leveraging a Sr transition in the mid-infrared, we pursue the controlled creation of superradiant and subradiant states. [1] C. Warner et al., Overlapping Bose-Einstein Condensates of Na and Cs, Phys. Rev. A 104, 033302 (2021). [2] I. Stevenson et al., Ultracold Gases of Dipolar NaCs Ground State Molecules, Phys. Rev. Lett. 130, 113002 (2023). [3] N. Bigagli et al., Collisionally Stable Gas of Bosonic Dipolar Ground State Molecules, arXiv:2303.16845 (2023). [4] M. Kwon, A. Holman, et al. Jet-loaded cold atomic beam source for strontium, Rev. Sci. Instr. 94, 013202 (2023). [5] X. Huang, W. Yuan, et al. Metasurface Holographic Optical Traps for Ultracold Atoms, Prog. Quantum Electr. 100470 (2023).

Sebastian Will is a professor of experimental quantum physics at Columbia University. He and his team work towards single atom and single molecule control for applications in fundamental science, quantum sensing, quantum simulation, and quantum computing. Sebastian has received the MIT Infinite Kilometer Award, the Columbia RISE Award, the NSF Career Award, and a Fellow of the Alfred P. Sloan Foundation.

Phonons in piezoelectric materials have played a pivotal role in radio-frequency signal processing since the advent of the crystal oscillator 100 years ago. Fast-forward to today: we all carry dozens of piezoelectric acoustic wave devices in our pockets, and many promising quantum information processing systems use phonons as a means to mediate interactions between different qubit modalities. However, the phonons in all these examples behave completely linearly. What could we do with phonons if we could enter the regime of strongly nonlinear phononics? In this talk, I will describe a methodology my group has developed to create very strong microwave frequency phononic nonlinearities that now puts us squarely in that regime. I will discuss recent results on phononic phase-preserving amplification, frequency conversion, and phononic Kerr nonlinearity. I will also discuss the prospects of this work looking forward, where these systems may hold the key to an era of quantum phononics with functionality and performance that rivals that of quantum photonics.

Matt Eichenfield is an Associate Professor and the SPIE Endowed Chair in the University of Arizona’s College of Optical Sciences, as well as a Distinguished Faculty Joint Appointee at Sandia National Labs. He received his BS in physics from UNLV in 2004 and his PhD in physics from Caltech in 2010 in the group of Professor Oskar Painter. After finishing his PhD, he was Caltech's first Kavli Nanoscience Prize Postdoctoral Fellow before joining Sandia as a Harry S. Truman Fellow in 2011. At Sandia he founded and led the MEMS-Enabled Quantum Systems group and conducted research there on integrated photonics, phononics, and sensing. He began his joint appointment with UA and Sandia in 2022 and now has research groups at both institutions.

Long distance quantum implementations would strongly benefit from the use of photons as carriers of information. In both free-space connections, as well as fibre-based networks, the use of light within telecommunication bands will have various advantages. As exemplary in glass fibres, the backbone of our communication infrastructures, the use of quantum light in the so-called telecom O- (centred around 1310 nm) and C-band (centred around 1550 nm) would have the advantages of experiencing minimal photon wavepacket dispersion and absorption. Semiconductor quantum dots are considered as very appealing sources of quantum light, in particular the systems based on the GaAs material platform. We will discuss the techniques that can be employed to realize In(Ga)As/GaAs quantum dots emitting in the telecom O- and C-bands [1]. Furthermore, we will discuss advanced fabrication techniques [2] and optical resonators that can be employed to enhance the source brightness and performances, even operating at liquid nitrogen temperature [3]. Finally, In(Ga)As QDs emitting in the telecom C-band will be integrated into circular Bragg grating cavities. Thanks to Purcell enhancement, a fibre-coupled single-photon count rate of 13.9 MHz is observed (excitation rep. rate of 228 MHz, first-lens collection efficiency ~17%), with a multi-photon contribution as low as g(2)(0) = 0.0052. Operation up to 40K will be discussed [4]. [1] S. L. Portalupi, et al., Semicond. Sci. Technol. 34, 053001 (2019) [2] M. Sartison, et al., Appl. Phys. Lett. 113, 032103 (2018) [3] S. Kolatschek, et al., Nano Lett. 21, 7740 (2021) [4] C. Nawrath, et al., ArXiv 2207.12898 (2022).

Simone Luca Portalupi received his Ph.D. in physics from the University of Pavia, Italy in 2012, working on silicon photonics and spectroscopy of nanostructures and fabrication of photonic crystal cavities (last topic in St. Andrews, UK). As post-doctoral fellow (CNRS in Paris, France), he researched on semiconductor quantum dots (III–V platform), cavity quantum electrodynamics, and deterministic nanofabrication techniques. Currently, he is group leader of the quantum optics group at the IHFG,University of Stuttgart, Germany. His research focuses on quantum optics with semiconductor quantum dots, integrated quantum photonics, hybrid quantum systems, long-distance quantum communication and implementation of advanced nanofabrication techniques.