Physics:Quantum jump method: Difference between revisions

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The '''quantum jump method''', also known as the '''[[Monte Carlo method|Monte Carlo]] wave function (MCWF)''' is a technique in [[Physics:Computational physics|computational physics]] used for simulating [[Physics:Open quantum system|open quantum system]]s and [[Physics:Quantum dissipation|quantum dissipation]]. The quantum jump method was developed by [[Biography:Jean Dalibard|Dalibard]], Castin and [[Biography:Klaus Mølmer|Mølmer]] at a similar time to the similar method known as [[Physics:Quantum Trajectory Theory|Quantum Trajectory Theory]] developed by [[Biography:Howard Carmichael|Carmichael]]. Other contemporaneous works on wave-function-based [[Monte Carlo method|Monte Carlo]] approaches to open quantum systems include those of Dum, [[Biography:Peter Zoller|Zoller]] and [[Biography:Helmut Ritsch|Ritsch]] and Hegerfeldt and Wilser.<ref name="MCD1993" /><ref name="PrimaryPapers">The associated primary sources are, respectively:
The '''quantum jump method''', also known as the '''Monte Carlo wave function (MCWF)''' is a technique in computational physics used for simulating open quantum systems and [[Physics:Quantum dissipation|quantum dissipation]]. The quantum jump method was developed by [[Biography:Jean Dalibard|Dalibard]], Castin and [[Biography:Klaus Mølmer|Mølmer]] at a similar time to the similar method known as [[Physics:Quantum Trajectory Theory|Quantum Trajectory Theory]] developed by [[Biography:Howard Carmichael|Carmichael]]. Other contemporaneous works on wave-function-based Monte Carlo approaches to open quantum systems include those of Dum, [[Biography:Peter Zoller|Zoller]] and [[Biography:Helmut Ritsch|Ritsch]] and Hegerfeldt and Wilser.<ref name="MCD1993" /><ref name="PrimaryPapers">The associated primary sources are, respectively:


*{{cite journal|last=Dalibard|first=Jean|author2=Castin, Yvan |author3=Mølmer, Klaus |title=Wave-function approach to dissipative processes in quantum optics|journal=Physical Review Letters|date=February 1992|volume=68|issue=5|pages=580–583|doi=10.1103/PhysRevLett.68.580|pmid=10045937|bibcode = 1992PhRvL..68..580D |arxiv=0805.4002}}
*{{cite journal|last=Dalibard|first=Jean|author2=Castin, Yvan |author3=Mølmer, Klaus |title=Wave-function approach to dissipative processes in quantum optics|journal=Physical Review Letters|date=February 1992|volume=68|issue=5|pages=580–583|doi=10.1103/PhysRevLett.68.580|pmid=10045937|bibcode = 1992PhRvL..68..580D |arxiv=0805.4002}}
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[[File:Master_equation_unravelings.svg|thumb|280px|jump method in the Quantum Collection.]]
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== Method ==
== Method ==
[[File:Master equation unravelings.svg|thumb|An example of the quantum jump method being used to approximate the density matrix of a two-level atom undergoing damped [[Rabi oscillation]]s. The random jumps can clearly be seen in the top subplot, and the bottom subplot compares the fully simulated density matrix to the approximation obtained using the quantum jump method.]]
[[File:Master equation unravelings.svg|thumb|An example of the quantum jump method being used to approximate the density matrix of a two-level atom undergoing damped Rabi oscillations. The random jumps can clearly be seen in the top subplot, and the bottom subplot compares the fully simulated density matrix to the approximation obtained using the quantum jump method.]]


[[File:MC-ensemble average.gif|thumb|Animation of the Monte Carlo prediction (blue) for the population of a coherently-driven, damped two-level system as more trajectories are added to the ensemble average, compared to the master equation prediction (red).]]
[[File:MC-ensemble average.gif|thumb|Animation of the Monte Carlo prediction (blue) for the population of a coherently-driven, damped two-level system as more trajectories are added to the ensemble average, compared to the master equation prediction (red).]]


The quantum jump method is an approach which is much like the master-equation treatment except that it operates on the wave function rather than using a [[Density matrix|density matrix]] approach. The main component of this method is evolving the system's wave function in time with a pseudo-Hamiltonian; where at each time step, a quantum jump (discontinuous change) may take place with some probability. The calculated system state as a function of time is known as a [[Quantum stochastic calculus#Quantum trajectories|quantum trajectory]], and the desired [[Density matrix|density matrix]] as a function of time may be calculated by averaging over many simulated trajectories. For a Hilbert space of dimension N, the number of wave function components is equal to N while the number of density matrix components is equal to N<sup>2</sup>. Consequently, for certain problems the quantum jump method offers a performance advantage over direct master-equation approaches.<ref name=MCD1993>{{Cite journal | last1 = Mølmer | first1 = K. | last2 = Castin | first2 = Y. | last3 = Dalibard | first3 = J. | doi = 10.1364/JOSAB.10.000524 | title = Monte Carlo wave-function method in quantum optics | journal = Journal of the Optical Society of America B | volume = 10 | issue = 3 | pages = 524 | year = 1993 |bibcode = 1993JOSAB..10..524M }}</ref>
The quantum jump method is an approach which is much like the master-equation treatment except that it operates on the wave function rather than using a density matrix approach. The main component of this method is evolving the system's wave function in time with a pseudo-Hamiltonian; where at each time step, a quantum jump (discontinuous change) may take place with some probability. The calculated system state as a function of time is known as a quantum trajectory, and the desired density matrix as a function of time may be calculated by averaging over many simulated trajectories. For a Hilbert space of dimension N, the number of wave function components is equal to N while the number of density matrix components is equal to N<sup>2</sup>. Consequently, for certain problems the quantum jump method offers a performance advantage over direct master-equation approaches.<ref name=MCD1993>{{Cite journal | last1 = Mølmer | first1 = K. | last2 = Castin | first2 = Y. | last3 = Dalibard | first3 = J. | doi = 10.1364/JOSAB.10.000524 | title = Monte Carlo wave-function method in quantum optics | journal = Journal of the Optical Society of America B | volume = 10 | issue = 3 | pages = 524 | year = 1993 |bibcode = 1993JOSAB..10..524M }}</ref>


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== External links ==
== External links ==
* [http://qutip.org/docs/latest/guide/dynamics/dynamics-monte.html mcsolve] {{Webarchive|url=https://web.archive.org/web/20230930194128/https://qutip.org/docs/latest/guide/dynamics/dynamics-monte.html |date=2023-09-30 }} Quantum jump ([[Monte Carlo method|Monte Carlo]]) solver from [[Software:QuTiP|QuTiP]] for [[Python (programming language)|Python]].
* [http://qutip.org/docs/latest/guide/dynamics/dynamics-monte.html mcsolve] {{Webarchive|url=https://web.archive.org/web/20230930194128/https://qutip.org/docs/latest/guide/dynamics/dynamics-monte.html |date=2023-09-30 }} Quantum jump (Monte Carlo) solver from QuTiP for Python.
* [https://qojulia.org QuantumOptics.jl] the quantum optics toolbox in [[Julia (programming language)|Julia]].
* [https://qojulia.org QuantumOptics.jl] the quantum optics toolbox in Julia.
* [https://qo.phy.auckland.ac.nz/toolbox/ Quantum Optics Toolbox] for [[Software:MATLAB|Matlab]]
* [https://qo.phy.auckland.ac.nz/toolbox/ Quantum Optics Toolbox] for Matlab


[[Category:Quantum mechanics]]
[[Category:Quantum mechanics]]
[[Category:Computational physics]]
[[Category:Computational physics]]
[[Category:Monte Carlo methods]]
[[Category:Monte Carlo methods]]


{{Sourceattribution|Quantum jump method}}
{{Sourceattribution|Quantum jump method}}

Latest revision as of 23:34, 23 May 2026


The quantum jump method, also known as the Monte Carlo wave function (MCWF) is a technique in computational physics used for simulating open quantum systems and quantum dissipation. The quantum jump method was developed by Dalibard, Castin and Mølmer at a similar time to the similar method known as Quantum Trajectory Theory developed by Carmichael. Other contemporaneous works on wave-function-based Monte Carlo approaches to open quantum systems include those of Dum, Zoller and Ritsch and Hegerfeldt and Wilser.[1][2]

jump method in the Quantum Collection.

Method

An example of the quantum jump method being used to approximate the density matrix of a two-level atom undergoing damped Rabi oscillations. The random jumps can clearly be seen in the top subplot, and the bottom subplot compares the fully simulated density matrix to the approximation obtained using the quantum jump method.
Animation of the Monte Carlo prediction (blue) for the population of a coherently-driven, damped two-level system as more trajectories are added to the ensemble average, compared to the master equation prediction (red).

The quantum jump method is an approach which is much like the master-equation treatment except that it operates on the wave function rather than using a density matrix approach. The main component of this method is evolving the system's wave function in time with a pseudo-Hamiltonian; where at each time step, a quantum jump (discontinuous change) may take place with some probability. The calculated system state as a function of time is known as a quantum trajectory, and the desired density matrix as a function of time may be calculated by averaging over many simulated trajectories. For a Hilbert space of dimension N, the number of wave function components is equal to N while the number of density matrix components is equal to N2. Consequently, for certain problems the quantum jump method offers a performance advantage over direct master-equation approaches.[1]


References

  1. 1.0 1.1 Mølmer, K.; Castin, Y.; Dalibard, J. (1993). "Monte Carlo wave-function method in quantum optics". Journal of the Optical Society of America B 10 (3): 524. doi:10.1364/JOSAB.10.000524. Bibcode: 1993JOSAB..10..524M. 
  2. The associated primary sources are, respectively:

Further reading

  • Plenio, M. B.; Knight, P. L. (1 January 1998). "The quantum-jump approach to dissipative dynamics in quantum optics". Reviews of Modern Physics 70 (1): 101–144. doi:10.1103/RevModPhys.70.101. Bibcode: 1998RvMP...70..101P. 

Source attribution: Quantum jump method