Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Static Stern-Gerlach effect in magnetic force microscopy

G. P. Berman, G. D. Doolen, P. C. Hammel, V. I. Tsifrinovich

Published Feb 20, 2002• 7 citations
Publisher

Abstract

We examine static single-spin measurements using magnetic-force microscopy methods. We show that these measurements could be carried out at millikelvin temperatures. A simple estimate of the decoherence time is presented. Possible experiments for measuring single-spin relaxation processes and the use of these measurements in quantum computations are discussed.

DOI
10.1103/physreva.65.032311

Related papers

Transient dynamics in magnetic force microscopy for a single-spin measurement

G. P. Berman, F. Borgonovi, Gustavo V. López +1 more

We analyze a single-spin measurement using a transient process in magnetic force microscopy which could increase the maximum operating temperature by a factor of Q (the quality factor of the cantilever) in comparison with the static Stern-Gerlach effect. We obtain an exact solution of the master equation, which confirms this result. We also discuss the conditions required to create a macroscopic quantum superposition in the cantilever.

arXiv:quant-ph/0210006•Physical Review A•Jul 9, 2003•7 citations

Theory of Scanning Tunneling Microscopy Measurement of Single Spin Decoherence in a Superconductor

Jurij Šmakov, Ivar Martin, Alexander V. Balatsky

Localized spin states in conventional superconductors at low temperatures are expected to have a long decoherence time due to the strong suppression of spin relaxation channels. We propose a scanning tunneling microscopy (STM) experiment allowing the direct measurement of the decoherence time of a single spin in a conventional superconductor. The experimental setup can be readily applied to general-purpose spin-polarized STM and to local spin relaxation spectroscopy. A possible extension of the setup to a quantum information processing scheme is discussed.

Physical Review Letters•Jan 2, 2002•8 citations

Application of magnetic resonance force microscopy cyclic adiabatic inversion for a single-spin measurement

G. P. Berman, F. Borgonovi, George Chapline +5 more

We consider the process of a single-spin measurement using magnetic resonance force microscopy (MRFM) with a cyclic adiabatic inversion (CAI). This technique is also important for different applications, including a measurement of a qubit state in quantum computation. The measurement takes place through the interaction of a single spin with a cantilever modelled by a quantum oscillator in a coherent state in a quasi-classical range of parameters. The entire system is treated rigorously within the framework of the Schrödinger equation. For a many-spin system our equations accurately describe conventional MRFM experiments involving CAI of the spin system. Our computer simulations of the quantum spin–cantilever dynamics show that the probability distribution for the cantilever position develops two asymmetric peaks with the total relative probabilities mainly dependent on the initial angle between the directions of the average spin and the effective magnetic field, in the rotating frame. We show that each of the peaks is correlated with the direction of the average spin (being along or opposite to the direction of the effective magnetic field). This generates two possible outcomes of a single-spin measurement, similar to the Stern–Gerlach effect. We demonstrate that the generation of the second peak can be significantly suppressed by turning on adiabatically the amplitude of the rf magnetic field. We also show that MRFM CAI can be used both for detecting a signal from a single spin, and for measuring the single-spin state by measuring the phase of the cantilever driving oscillations.

arXiv:quant-ph/0108025•Journal of Physics A Mathematical and General•Apr 2, 2003•12 citations

The Stern–Gerlach experiment and the effects of spin relaxation

Håkan Wennerström, Per-Olof Westlund

The classical Stern-Gerlach experiment is analyzed with an emphasis on the spin dynamics. The central question asked is whether there occurs a relaxation of the spin angular momentum during the time the particle passes through the Stern-Gerlach magnet. We examine in particular the transverse relaxation, involving angular momentum exchange between the spin of the particles and the spins of the magnet. A method is presented describing relaxation effects at an individual particle level. This leads to a stochastic equation of motion for the spins. This is coupled to a classical equation of motion for the particle translation. The experimental situation is then modeled through simulations of individual trajectories using two sets of parameter choices and three different sets of initial conditions. The two main conclusions are: (A) if the coupling between the magnet and the spin is solely described by the Zeeman interaction with the average magnetic field the simulations show a clear disagreement with the experimental observation of Stern and Gerlach. (B) If one, on the other hand, also allows for a T(2) relaxation time shorter than the passage time one can obtain a practically quantitative agreement with the experimental observations. These conclusions are at variance with the standard textbook explanation of the Stern-Gerlach experiment.

Physical Chemistry Chemical Physics•Dec 23, 2011•20 citations

Single-spin measurement and decoherence in magnetic-resonance force microscopy

G. P. Berman, F. Borgonovi, Hsi‐Sheng Goan +2 more

We consider a simple version of a cyclic adiabatic inversion (CAI) technique in magnetic-resonance force microscopy (MRFM). We study the problem: What component of the spin is measured in the CAI MRFM? We show that the nondestructive detection of the cantilever vibrations provides a measurement of the spin component along the effective magnetic field. This result is based on numerical simulations of the Hamiltonian dynamics (the Schr\"odinger equation) and the numerical solution of the master equation.

arXiv:quant-ph/0210043•Physical review. B, Condensed matter•Mar 27, 2003•21 citations

Realistic simulations of single-spin nondemolition measurement by magnetic resonance force microscopy

Todd A. Brun, Hsi‐Sheng Goan

A requirement for many quantum computation schemes is the ability to measure single spins. This paper examines one proposed scheme: magnetic resonance force microscopy (MRFM), including the effects of thermal noise and back action from monitoring. We derive a simplified equation using the adiabatic approximation and produce a stochastic pure state unraveling which is useful for numerical simulations. We also calculate the signal-to-noise ratio for single-spin measurement by MRFM, using a quantum Langevin equation approach.

arXiv:quant-ph/0302178•Physical Review A•Sep 5, 2003•26 citations
We examine static single-spin measurements using magnetic-force microscopy methods. We show that these measurements could be carried out at millikelvin temperatures. A simple estimate of the decoherence time is presented. Possible experiments for measuring single-spin relaxation processes and the use of these measurements in quantum computations are discussed.
Localized spin states in conventional superconductors at low temperatures are expected to have a long decoherence time due to the strong suppression of spin relaxation channels. We propose a scanning tunneling microscopy (STM) experiment allowing the direct measurement of the decoherence time of a single spin in a conventional superconductor. The experimental setup can be readily applied to general-purpose spin-polarized STM and to local spin relaxation spectroscopy. A possible extension of the setup to a quantum information processing scheme is discussed.
We consider the process of a single-spin measurement using magnetic resonance force microscopy (MRFM) with a cyclic adiabatic inversion (CAI). This technique is also important for different applications, including a measurement of a qubit state in quantum computation. The measurement takes place through the interaction of a single spin with a cantilever modelled by a quantum oscillator in a coherent state in a quasi-classical range of parameters. The entire system is treated rigorously within the framework of the Schrödinger equation. For a many-spin system our equations accurately describe conventional MRFM experiments involving CAI of the spin system. Our computer simulations of the quantum spin–cantilever dynamics show that the probability distribution for the cantilever position develops two asymmetric peaks with the total relative probabilities mainly dependent on the initial angle between the directions of the average spin and the effective magnetic field, in the rotating frame. We show that each of the peaks is correlated with the direction of the average spin (being along or opposite to the direction of the effective magnetic field). This generates two possible outcomes of a single-spin measurement, similar to the Stern–Gerlach effect. We demonstrate that the generation of the second peak can be significantly suppressed by turning on adiabatically the amplitude of the rf magnetic field. We also show that MRFM CAI can be used both for detecting a signal from a single spin, and for measuring the single-spin state by measuring the phase of the cantilever driving oscillations.
The classical Stern-Gerlach experiment is analyzed with an emphasis on the spin dynamics. The central question asked is whether there occurs a relaxation of the spin angular momentum during the time the particle passes through the Stern-Gerlach magnet. We examine in particular the transverse relaxation, involving angular momentum exchange between the spin of the particles and the spins of the magnet. A method is presented describing relaxation effects at an individual particle level. This leads to a stochastic equation of motion for the spins. This is coupled to a classical equation of motion for the particle translation. The experimental situation is then modeled through simulations of individual trajectories using two sets of parameter choices and three different sets of initial conditions. The two main conclusions are: (A) if the coupling between the magnet and the spin is solely described by the Zeeman interaction with the average magnetic field the simulations show a clear disagreement with the experimental observation of Stern and Gerlach. (B) If one, on the other hand, also allows for a T(2) relaxation time shorter than the passage time one can obtain a practically quantitative agreement with the experimental observations. These conclusions are at variance with the standard textbook explanation of the Stern-Gerlach experiment.
We consider a simple version of a cyclic adiabatic inversion (CAI) technique in magnetic-resonance force microscopy (MRFM). We study the problem: What component of the spin is measured in the CAI MRFM? We show that the nondestructive detection of the cantilever vibrations provides a measurement of the spin component along the effective magnetic field. This result is based on numerical simulations of the Hamiltonian dynamics (the Schr\"odinger equation) and the numerical solution of the master equation.
A requirement for many quantum computation schemes is the ability to measure single spins. This paper examines one proposed scheme: magnetic resonance force microscopy (MRFM), including the effects of thermal noise and back action from monitoring. We derive a simplified equation using the adiabatic approximation and produce a stochastic pure state unraveling which is useful for numerical simulations. We also calculate the signal-to-noise ratio for single-spin measurement by MRFM, using a quantum Langevin equation approach.