In the News

June 11, 2018

Brown lab at 2018 DAMOP conference

Presentations:  Natalie Brown:  Comparing Zeeman qubits to hyperfine qubits in the context of the surface code: 171Yb+ and 174Yb+ ( Kisra Egodapitiya: Study of Cold Phase Chemistry Using a Hybrid Atom-Ion Setup ( [...]

June 10, 2018

EPiQC Kickoff Meeting and ISCA Tutorial

  Ken Brown presented a tutorial on the variational quantum eigensolver as part of the EPiQC tutorials at ISCA 2018 . The next day the EPiQC kickoff meeting was held in Anaheim and attended by Ken, James Leung, Dripto Debroy, and Muyauan Li from the Brown lab.

May 24, 2018

Coherent errors and quantum error correction

Our paper "Coherence in quantum error-correcting codes" led by collaborators at the University of Waterloo has been posted to the arXiv (arXiv:1805.08802) There are many ways that errors arise in quantum computers.  If the error is due to a fast noise process, then it can often be described by an [...]

cold ion

May 19, 2018

Magneto optically trapped K39 atoms in Brown lab at Duke

We successfully moved the cold ion, atom and molecule experimental setup from Georgia Tech to Duke.

May 18, 2018

Muyuan speaks at the Southeast Quantum Computing Workshop

Graduate student Muyuan Li delivered an invited presentation at the 2nd Annual Southeast Quantum Computing Workshop. Muyuan spoke about his recent work numerical work comparing the surface and Bacon-Shor quantum error correcting codes in the context of a trapped ion quantum computer. Details of the [...]

May 18, 2018

Aaron Calvin defends his thesis

 Aaron Calvin successfully defended his thesis Rovibronic Spectroscopy of Sympathetically Cooled CaH+ in Coulomb Crystals on May 17, 2018.  Congratulations to Dr. Calvin!    

May 14, 2018

Comparison of hyperfine and Zeeman qubits published in PRA

Is it worse to have leakage from the qubit manifold or sensitivity to magnetic field fluctuationss?  In the context of the surface code and ion qubits, the answer depends on the stability of the magnetic field.  For details see Brown and Brown, Phys. Rev. A 97, 052301 (2018)

April 26, 2018

Study of small surface code and ion traps published in New J. Phys.

Quantum error correction is critical for building high quality qubits from error prone parts.  The distance-3 surface code is a promising small code for implementing a quantum memory and trapped atomic ions are a leading implementation for quantum information processing. We numerically examined [...]

April 17, 2018

Spectator and data qubits

Qubits are more prone to errors than classical bits due to imperfections in controls and unwanted interaction with the environment. Measuring these noise sources can be difficult and often the qubit itself is the best detector.  The Brown Lab is part of a joint US and Australia Multi-University [...]

April 6, 2018

Direct measurement of Bacon-Shor stabilizers

The Bacon-Shor code is a fascinating quantum error correction code that has a simple description in terms of two redundancy codes, can be derived from a compass model of interacting spins, and is a subsystem code, whose extra degrees of freedom allows for syndrome extraction from measuring gauge [...]

March 26, 2018

Rovibronic spectra of CaH+ published in J. Phys. Chem. A

The first measurement of the rovibronic structure of CaH+ published in J. Phys. Chem. A.  The spectra was taken using resonance-enhanced multi-photon dissociation of CaH+ embedded in a Coulomb crystal of laser-cooled Ca+. A. T. Calvin, S. Janardan, J. Condoluci, R. Rugango, E. Pretzsch, G. Shu, and [...]

March 26, 2018

Comparing ion qubits in the context of the surface code

Which qubit is better: A qubit that is sensistive to magnetic field fluctuations, but has no leakage states, or a qubit that is insensitive to magnetic field fluctuations, but can leak outside of the qubit levels during gates?  We answer this question in the context of Zeeman and hyperfine qubits [...]

January 2, 2018

Brown Lab moves to Duke

After 11 years at Georgia Tech, the Brown Lab has moved to Duke University and is housed at the Chesterfield Building in downtown Durham.