Shuo, Genyue, Pai and Bichen demonstrate metastable nuclear spin qubits in 171Yb. This gives two big advantages over ground state qubits: fast Rydberg excitation (we now reach gate fidelities > 0.98), and the first demonstration of erasure conversion! [arXiv:2305.05493]

This was the result of a great collaboration with Sven Jandura and Guido Pupillo, and Jahan Claes and Shruti Puri.

See also had several recent theory papers related to these collaborative efforts:

• Optimizing Rydberg Gates for Logical Qubit Performance [Jandura, Thompson, Pupillo]

• High threshold codes for neutral atom qubits with biased erasure errors [Sahay, Jin, Claes, Thompson, Puri]

Update 10/11/23: This work is published in Nature (together with related artciles from Endres and Lukin groups)! [Press release]

[Posted 5/12/23]

Salim, Lukasz, Sebastian, Tuna and the team demonstrated indistinguishable single photon emission from a single Er3+ ion, opening the door to telecom-band spin-photon entanglement and quantum repeaters in the near future! This was enabled by our years-long effort to study ion implantation of Er into new host materials, in collaboration with Bob Cava, Nathalie de Leon and Steve Lyon. In this work, Er implanted at a depth of just 10 nm in CaWO4 has homogeneous optical linewidths at the 100 kHz level! [arXiv:2301.03564]

[Posted 5/12/23]

Update 8/23: This work appeared in Nature, with a summary by Jeff and Lukasz! There is also a Princeton press release.

Two exciting developments in quantum computing with Yb:

1. We have implemented the first universal qubit operations in an AEA qubit, in 171Yb.

2. Together with Shimon Kolkowitz and Shruti Puri, we proposed a very efficient error correction protocol based on metastable state qubits in the 3P0 level, and converting Rydberg decay errors into directly detectable erasures.

[Posted 1/11/22]

Update 5/3/22: Shuo, Alex, Jack, Genyue and Bichen's 171Yb paper is published in PRX, with an accompanying synopsis in Physics.

Update 8/22: Error correction paper is published in Nature Comms. Also, our work on AEA qubits in general is featured in a great Physics Today article by Ben Brubaker.

A new paper by Alex Burgers et al (in collaboration with the group of Chris Greene) demonstrates a new approach to controlling how atoms in a Yb optical tweezer array are excited to Rydberg states. Specifically, this work shows that optical transitions in the Yb+ ion core can be used to apply a light shift to the Rydberg states, which compares very favorably with shifting the ground state in terms of the control power required to realize a certain gate fidelity. This points the way to scalable local addressing of high-fidelity gate operations.

[Posted 10/14/21]

A new paper by Stevenson et al, in collaboration with the groups of Philippe Goldner, Ramamoorthy Ramesh, Bob Cava and Nathalie de Leon, characterizes Er3+ ion incorporation into a wide range of new host materials. This work demonstrates that materials and thermal processing techniques can be rapidly screened, and points to several promising, new materials for developing single-emitter devices.

[Posted 10/14/21]

Congratulations to Dr. Chris Phenicie for defending his thesis, "Devices and Materials for Quantum Networks based on Rare Earth Ions"!

[Posted 10/8/2021]

In April, Mouktik successfully defended his PhD thesis (the first from the lab)! We wish him the best in his postdoc at the University of Chicago.

In July, Songtao started his own group at Rice University, in the department of Electrical and Computer Engineering!

[Posted 7/26/21]

A new paper by Sam Cohen and Jeff describes an approach to quantum computing/simulation with circular Rydberg atoms in optical tweezers! These atoms can have lifetimes exceeding 20 seconds in the right environment, opening new directions for extremely coherent and high fidelity operations. There are openings for students and postdocs to work on this project--please get in touch!

[8/21 - Published in PRX Quantum!]

[Posted 3/25/21]

Songtao et al. have posted a paper describing our new technical approach for coupling light and microwaves to our devices inside a cryostat!

[Posted 12/18/20]

[Update 2/1/21] Published in Optics Express!

Songtao, Mouktik et al. posted a paper describing parallel single-shot readout and coherent manipulation of up to six Erbium atoms with deep sub-wavelength spacing, using frequency-domain addressing. This is a major step towards realizing interacting rare earth ion arrays for quantum information processing and studies of many-body dynamics.

[Posted 6/2/20]

[Update 10/29/20] Published in Science!

Mouktik et al. posted a paper describing QND, single-shot spin readout of a single Erbium ion. This is achieved using a novel technique, where selection rules from the atom-cavity coupling are used to introduce a cycling transition. The paper also measures spin T1 times as long as 12 seconds, and coherent manipulation of the spin with microwave fields.

[Posted 7/24/19]

[Update 3/30/20]

This work was published in Nature Comms., with a News & Views by Wrachtrup and Kolesov in Nature Physics!

Jack, Sam, Yijian, Shuo, Rohit and Alex posted the first paper on alkaline earth atoms in Rydberg states. In addition to performing some novel spectroscopy of the 3S1 series, they demonstrate a key advantage of this platform: trapping Rydberg states using the polarizability of the ion core.

[Posted 12/19]

In collaboration with the groups of Nathalie de Leon, Steve Lyon and Bob Cava, Chris, Sacha and Paul have demonstrated in a new preprint that titanium dioxide (TiO2) looks like a promising host for Erbium ions! Implanted erbium ions are active with a high yield (at least 40%) and have an inhomogeneous optical linewidth comparable to or better than most traditional rare earth host crystals (420 MHz). TiO2 as a much lower abundance of nuclear spins than Y-based materials, and can in principle be further isotopically enriched.

[Update 12/2/19: published in Nano Letters!]

[Posted 9/15/19]

Jack, Sam and Brandon posted a paper describing the first result of our atomic physics effort: creating large-scale arrays of laser-cooled Ytterbium atoms in optical tweezers!

[Update 1/3/19: This work was featured alongside Sr tweezer arrays in a recent Physics Viewpoint.]

[4/11/19: published in PRL; see also Nature News and Views by Mark Saffman]

[Posted 10/24/18]