Alexei M. Tyryshkin

Will Spin-Relaxation Times in Molecular Magnets Permit Quantum Information Processing?

Using X-band pulsed electron-spin resonance, we report the intrinsic spin-lattice (T1) and phase-coherence (T2) relaxation times in molecular nanomagnets for the first time. In Cr7M heterometallic wheels, with M=Ni and Mn, phase-coherence relaxation is dominated by the coupling of the electron spin to protons within the molecule. In deuterated samples T2 reaches 3 micros at low temperatures, which is several orders of magnitude longer than the duration of spin manipulations, satisfying a prerequisite for the deployment of molecular nanomagnets in quantum information applications.

Electron spin coherence exceeding seconds in high-purity silicon

Silicon is one of the most promising semiconductor materials for spin-based information processing devices. Its advanced fabrication technology facilitates the transition from individual devices to large-scale processors, and the availability of a (28)Si form with no magnetic nuclei overcomes a primary source of spin decoherence in many other materials. Nevertheless, the coherence lifetimes of electron spins in the solid state have typically remained several orders of magnitude lower than that achieved in isolated high-vacuum systems such as trapped ions. Here we examine electron spin coherence of donors in pure (28)Si material (residual (29)Si concentration <50 ppm) with donor densities of 10(14)-10(15) cm(-3). We elucidate three mechanisms for spin decoherence, active at different temperatures, and extract a coherence lifetime T(2) up to 2 s. In this regime, we find the electron spin is sensitive to interactions with other donor electron spins separated by ~200 nm. A magnetic field gradient suppresses such interactions, producing an extrapolated electron spin T(2) of 10 s at 1.8 K. These coherence lifetimes are without peer in the solid state and comparable to high-vacuum qubits, making electron spins of donors in silicon ideal components of quantum computers, or quantum memories for systems such as superconducting qubits.

Electron spin relaxation times of phosphorus donors in silicon

Donor electron spins in phosphorus-doped silicon (Si:P) are a candidate two-level system (qubit) for quantum information processing. Spin echo measurements of isotopically purified

Solid-state quantum memory using the 31P nuclear spin

{}^{28}\mathrm{S}\mathrm{i}:\mathrm{P}

Electron spin relaxation of N@C60 in CS2

are presented that show exceptionally long transverse relaxation (decoherence) times,

High Fidelity Single Qubit Operations Using Pulsed Electron Paramagnetic Resonance

{T}_{2},

Coherence of spin qubits in silicon

at low temperature. Below

A new type of manganese-Schiff base complex, catalysts for the disproportionation of hydrogen peroxide as peroxidase mimics

\ensuremath{\sim}10\mathrm{K}

Electrical activation and electron spin coherence of ultralow dose antimony implants in silicon

the spin decoherence is shown to be controlled by instantaneous diffusion and at higher temperatures by an Orbach process.

Superconducting coplanar waveguide resonators for low temperature pulsed electron spin resonance spectroscopy

{T}_{2}