Terhal Group

Barbara Terhal (Leiden, 1969) is a professor at the EEMCS Department at the TU Delft and a staff member at QuTech since 2017. Terhal received her PhD degree Cum Laude from the University of Amsterdam in 1999 on “Quantum Algorithms and Quantum Entanglement”, making her the first person to get a PhD in quantum computing in the Netherlands.

During her PhD thesis work she developed the concept of an entanglement witness as opposed to a Bell inequality test for the detection of quantum entanglement. After her PhD thesis she was a postdoc at IBM Research at Yorktown Heights, NY and at Caltech, before returning to IBM as research staff member in 2001. Notable work during her IBM period are the exploration of the computational power of low-depth quantum circuits or stoquastic (sign-free) Hamiltonians, the use of perturbative gadgets for quantum simulation and quantum complexity theory and the development of quantum information procotols such as remote state preparation, quantum locking and quantum data hiding.

She has a long-standing interest and track-record in quantum error correction and fault-tolerance. She views a scalable implementation of quantum error correction as one of the great challenges in physics today. The fact that this challenge can be viewed both as a question of ‘mere engineering’ as well as a question about the fundamental viability of macroscopic quantum information (see e.g. the essay), is precisely what makes it fascinating and thus its resolution ground-breaking.

In 2010 she left IBM to become professor in theoretical physics at RWTH Aachen University, supplemented by a position at FZ Juelich from 2015 until present. She has been a fellow of the American Physical Society since 2007 and a distinguished visiting research chair at Perimeter Institute since 2014.

The current work on quantum error correction in the group is funded by a ERC consolidator grant. In addition, we are part of European Quantum Code Design and Architecture Consortium.

Students or postdocs with a theoretical bend who are interested in figuring out what to do with the partially-coherent qubits of the various QuTech platforms, or in learning what is going on in Terhal’s group, please contact

Significant Publications

B.M. Terhal, “Bell Inequalities and The Separability Criterion”, Physics Letters A 271, 319 (2000)

B.M. Terhal and D.P. DiVincenzo, “Adaptive quantum computation, constant depth quantum circuits, and Arthur Merlin games”, Quant. Inf. and Comp. 4:2, pp. 134-145 (2004)

R. Oliveira and B.M. Terhal, “The Complexity of Quantum Spin Systems on a Two-dimensional Square Lattice”, Quant. Inf. Comp. Volume 8, No. 10, pp. 0900-0924 (2008)

S. Bravyi and B.M. Terhal, “A No-Go Theorem for a Two-Dimensional Self-Correcting Memory Based on Stabilizer Codes”, New J. Phys. 11 (2009) 043029

B.M. Terhal, F. Hassler and D.P. DiVincenzo, “From Majorana Fermions to Topological Order”, Phys. Rev. Lett. 108, 260504 (2012)

B.M. Terhal, “Quantum Error Correction for Quantum Memories”, Rev. Mod. Phys. 87, 307 (2015)

K. Duivenvoorden, B.M. Terhal and D. Weigand, “Single-mode Displacement Sensor”, Phys. Rev. A 95, 012305 (2017)

E.T. Campbell, B.M. Terhal and C. Vuillot, “Roads towards fault-tolerant universal quantum computation”, Nature 549, 172 (2017)