Quantum Measurements using Diamond Spins: From Fundamental Tests to Long-Distance Teleportation

Spin qubits in diamond provide an excellent platform both for fundamental tests and for realizing extended quantum networks . Here we present our latest results, including the deterministic teleportation over three meters.

Manipulating a spin qubit by the backaction of sequential partial adaptive measurements

We report the control-free manipulation of a nuclear spin qubit in diamond, using only the backaction of sequential partial measurements with real-time feedback.

Quantum state steering by real-time adaptive measurements on a single nuclear spin

We present our most recent results on partial measurements of a nuclear spin in which the inevitable measurement back-action is controllably reduced. The post-selected measurement results can give rise to weak values. By using a real-time adaptive scheme the quantum state can be tuned using only measurements.

Diamond NV centers for quantum computing and quantum networks

The exotic features of quantum mechanics have the potential to revolutionize information technologies. Using superposition and entanglement, a quantum processor could efficiently tackle problems inaccessible to current-day computers. Nonlocal correlations may be exploited for intrinsically secure communication across the globe. Finding and...

Probing Dynamics of an Electron-Spin Ensemble via a Superconducting Resonator

We study spin relaxation and diffusion in an electron-spin ensemble of nitrogen impurities in diamond at low temperature (0.25–1.2 K) and polarizing magnetic field (80–300 mT). Measurements exploit field-controlled coupling of the ensemble to two modes of a transmission-line resonator. The observed temperature-independent spin relaxation time...

Quantum rekenen: Quantumcomputers en qubits

De quantum computer is een computer gebaseerd op quantum bits, kortweg qubits. Dat zijn bits die fysiek gemaakt zijn van quantum systemen, met de speciale eigenschap dat ze in een superpositie tussen twee toestanden kunnen zijn.

Top-down fabrication of plasmonic nanostructures for deterministic coupling to single quantum emitters

Metal nanostructures can be used to harvest and guide the emission of single photon emitters on-chip via surface plasmon polaritons. In order to develop and characterize photonic devices based on emitter-plasmon hybrid structures, a deterministic and scalable fabrication method for such structures is desirable. Here, we demonstrate deterministic...

Detection and Control of Individual Nuclear Spins Using a Weakly Coupled Electron Spin

We experimentally isolate, characterize, and coherently control up to six individual nuclear spins that are weakly coupled to an electron spin in diamond. Our method employs multipulse sequences on the electron spin that resonantly amplify the interaction with a selected nuclear spin and at the same time dynamically suppress decoherence caused...

Comparison of dynamical decoupling protocols for a nitrogen-vacancy center in diamond

We perform a detailed theoretical-experimental study of the dynamical decoupling (DD) of the nitrogen-vacancy (NV) center in diamond. We investigate the DD sequences applied to suppress the dephasing of the electron spin of the NV center induced by the coupling to a spin bath composed of the substitutional nitrogen atoms. The decoupling...

Effect of a nanoparticle on the optical properties of a photonic crystal cavity: Theory and experiment

Single quantum emitters can be coupled to photonic crystal (PC) cavities by placing their host nanoparticles into the cavity field. We describe fabrication, characterization, and tuning of gallium-phosphide PC cavities that resonate in the visible, and simulations and measurements of the effect of a nanoparticle on the optical properties of...

Two-Photon Quantum Interference from Separate Nitrogen Vacancy Centers in Diamond

We report on the observation of quantum interference of the emission from two separate nitrogen vacancy (NV) centers in diamond. Taking advantage of optically induced spin polarization in combination with polarization filtering, we isolate a single transition within the zero-phonon line of the nonresonantly excited NV centers. The time-resolved...

Charge-State Conditional Operation of a Spin Qubit

We report coherent operation of a singlet-triplet qubit controlled by the spatial arrangement of two confined electrons in an adjacent double quantum dot that is electrostatically coupled to the qubit. This four-dot system is the specific device geometry needed for two-qubit operations of a two-electron spin qubit. We extract the strength of the...

Deterministic nanoassembly of a coupled quantum emitter–photonic crystal cavity system

Controlling the interaction of a single quantum emitter with its environment is a key challenge in quantum optics. Here, we demonstrate deterministic coupling of single nitrogen-vacancy (NV) centers to high-quality photonic crystal cavities. We preselect single NV centers and position their 50-nm-sized host nanocrystals into the mode maximum of...

Single-Spin Magnetometry with Multipulse Sensing Sequences

We experimentally demonstrate single-spin magnetometry with multipulse sensing sequences. The use of multipulse sequences can greatly increase the sensing time per measurement shot, resulting in enhanced ac magnetic field sensitivity. We theoretically derive and experimentally verify the optimal number of sensing cycles, for which the effects of...

Single atom doping for quantum device development in diamond and silicon

The ability to inject dopant atoms with high spatial resolution, flexibility in dopant species, and high single ion detection fidelity opens opportunities for the study of dopant fluctuation effects and the development of devices in which function is based on the manipulation of quantum states in single atoms, such as proposed quantum computers....