In the News

October 19, 2018

Controlling error orientation

Quantum gates are difficult to implement and actual operations differ from their ideal operation. It is often convenient to measure the difference between the ideal operation and the actual operation by a single number such as the fidelity or the diamond distance.  Quantum operations have multiple [...]

October 5, 2018

Stabilizer Slicing: Coherent Error Cancellations in LDPC Codes

We recently posted a paper on the arXiv entitled "Stabilizer Slicing: Coherent Error Cancellations in LDPC Codes" in which we discuss a technique for applying stabilizers in a quantum error correcting code to minimize additional errors introduced into the system. The coherent errors we consider are [...]

October 5, 2018

Perspective on Spectroscopy in Coulomb Crystals published in JPCL

Aaron Calvin and Ken Brown's perspective on "Spectroscopy of Molecular Ions in Coulomb Crystals" published in J. Phys. Chem. Lett. and featured on the journal cover.   

September 10, 2018

2-D Compass Codes

  Our paper "2-D Compass Codes" has been uploaded to (arXiv:1809.01193). The compass model, a fundamental model in condensed matter physics, provides a natural template for building subsystem quantum error-correcting codes. The surface code and the Bacon-Shor code represent two extremes [...]

August 9, 2018

Entangling an arbitrary pair of qubits in a long ion crystal

  Our paper "Entangling an arbitrary pair of qubits in a long ion crystal" has been uploaded to (arXiv:1808.02555). Two-qubit gates are currently the "bottleneck" for accurate quantum operations. The ability to perform long-distance, high-fidelity two-qubit gates will significantly [...]

August 8, 2018

Announcing the STAQ project

Ken Brown is leading the Software-Tailored Architecture for Quantum co-design (STAQ) project, a multi-institute NSF funded collaborative research effort to build an ion trap quantum computer.  

June 28, 2018

First trapped ions at Duke

We trapped and laser-cooled calcium ions for the first time after moving into the new lab at Duke. Shown in the picture are the new calcium ion lasers, ion image, ion trap electronics, and the chamber. The setup is used to explore cold phase reactions with cold neutral potassium atoms in a MOT.

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 [...]