Engineering Dynamical Sweet Spots to Protect Qubits from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mi>f</mml:mi></mml:math> Noise

The sweet spots of a tennis racquet

Measurements are presented on the behaviour of a hand-held tennis racquet when it impacts with a tennis ball. It is shown that an impulse is transmitted through the racquet to the hand in about 1.5 ms, with the result that the hand and the forearm both have a strong in ̄uence on the behaviour of the racquet even while the ball is still in contact with the strings. Regardless of the impact point,...

Scaling of dynamical decoupling for spin qubits.

We investigate the scaling of coherence time T(2) with the number of π pulses n(π) in a singlet-triplet spin qubit using Carr-Purcell-Meiboom-Gill (CPMG) and concatenated dynamical decoupling (CDD) pulse sequences. For an even numbers of CPMG pulses, we find a power law T(2) is proportional to (n(π))(γ(e)), with γ(e)=0.72±0.01, essentially independent of the envelope function used to extract T(...

Decoherence in qubits due to low-frequency noise

The efficiency of the future devices for quantum information processing will be limited mostly by the finite decoherence rates of the qubits. Recently, substantial progress was achieved in enhancing the time within which a solid-state qubit demonstrates coherent dynamics. This progress is based mostly on a successful isolation of the qubits from external decoherence sources. Under these conditi...

Decoherence of flux qubits due to 1/f flux noise.

We have investigated decoherence in Josephson-junction flux qubits. Based on the measurements of decoherence at various bias conditions, we discriminate contributions of different noise sources. We present a Gaussian decay function extracted from the echo signal as evidence of dephasing due to 1/f flux noise whose spectral density is evaluated to be about (10(-6)Phi0)2/Hz at 1 Hz. We also demon...

Can physiology zap therapeutic sweet spots in hypertension?