Controlling and entangling a register of multiple quantum bits (qubits) is a key challenge in quantum information science. In this talk I will discuss our recent work on nitrogen-vacancy (NV) centers in diamond that enabled us to overcome two major challenges for spin-based quantum registers: protecting qubits from decoherence during gate operations and entangling weakly-interacting nuclear spins.

Decoherence due to the environment is a major hurdle towards realizing quantum devices, particularly in the solid-state. I will first present dynamical decoupling sequences that protect quantum states from decoherence during gate operations. With these decoherence-protected gates we executed a quantum algorithm in a room-temperature solid-state device with a total run time that exceeds the NV electron dephasing time by two orders of magnitude.

Second, I will discuss projective measurements as a unique resource for quantum information processing with well isolated qubits. We used a non-destructive qubit parity measurement to project two initially uncorrelated nuclear spins into maximally entangled states. The resulting high purity entangled states enabled us demonstrate for the first time a Bell’s inequality violation with solid state spins.


Seminar, September 27, 2012, 17:00. Seminar Room

Hosted by Prof. Niek van Hulst