Gaussian approximation and single-spin measurement in magnetic resonance force microscopy with spin noise

Journal Article · Mon Nov 15 00:00:00 EST 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.052319· OSTI ID:21528598

Raghunathan, Shesha; Brun, Todd A ^[1]; Goan, Hsi-Sheng ^[2]

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1. Center for Quantum Information Science and Technology, Communication Sciences Institute, Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States)
2. Department of Physics and Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan (China)

A promising technique for measuring single electron spins is magnetic resonance force microscopy (MRFM), in which a microcantilever with a permanent magnetic tip is resonantly driven by a single oscillating spin. The most effective experimental technique is the oscillating cantilever-driven adiabatic reversals (OSCAR) protocol, in which the signal takes the form of a frequency shift. If the quality factor of the cantilever is high enough, this signal will be amplified over time to the point where it can be detected by optical or other techniques. An important requirement, however, is that this measurement process occurs on a time scale that is short compared to any noise which disturbs the orientation of the measured spin. We describe a model of spin noise for the MRFM system and show how this noise is transformed to become time dependent in going to the usual rotating frame. We simplify the description of the cantilever-spin system by approximating the cantilever wave function as a Gaussian wave packet and show that the resulting approximation closely matches the full quantum behavior. We then examine the problem of detecting the signal for a cantilever with thermal noise and spin with spin noise, deriving a condition for this to be a useful measurement.

• OSTI ID: 21528598
• Journal Information: Physical Review. A, Vol. 82, Issue 5; Other Information: DOI: 10.1103/PhysRevA.82.052319; (c) 2010 The American Physical Society; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
97 MATHEMATICAL METHODS AND COMPUTING
APPROXIMATIONS
ELECTRONS
GAUSS FUNCTION
MAGNETIC RESONANCE
MICROSCOPY
NOISE
QUALITY FACTOR
QUANTUM INFORMATION
SPIN
TIME DEPENDENCE
WAVE FUNCTIONS
WAVE PACKETS
ANGULAR MOMENTUM
CALCULATION METHODS
DIMENSIONLESS NUMBERS
ELEMENTARY PARTICLES
FERMIONS
FUNCTIONS
INFORMATION
LEPTONS
PARTICLE PROPERTIES
RESONANCE