Jaynes–Cummings–Hubbard model

The Jaynes–Cummings–Hubbard (JCH) model is a many-body quantum system modeling the quantum phase transition of light. As the name suggests, the Jaynes–Cummings–Hubbard model is a variant on the Jaynes–Cummings model; a one-dimensional JCH model consists of a chain of N coupled single-mode cavities, each with a two-level atom. Unlike in the competing Bose–Hubbard model, Jaynes–Cummings–Hubbard dynamics depend on photonic and atomic degrees of freedom and hence require strong-coupling theory for treatment.[1] One method for realizing an experimental model of the system uses circularly-linked superconducting qubits.[2]

Tunnelling of photons between coupled cavities. The is the tunnelling rate of photons.
Illustration of the Jaynes–Cummings model. In the circle, photon emission and absorption are shown.

History

The JCH model was originally proposed in June 2006 in the context of Mott transitions for strongly interacting photons in coupled cavity arrays.[3] A different interaction scheme was synchronically suggested, wherein four level atoms interacted with external fields, leading to polaritons with strongly correlated dynamics.[4]

Properties

Using mean-field theory to predict the phase diagram of the JCH model, the JCH model should exhibit Mott insulator and superfluid phases.[5]

Hamiltonian

The Hamiltonian of the JCH model is ():

where are Pauli operators for the two-level atom at the n-th cavity. The is the tunneling rate between neighboring cavities, and is the vacuum Rabi frequency which characterizes to the photon-atom interaction strength. The cavity frequency is and atomic transition frequency is . The cavities are treated as periodic, so that the cavity labelled by n = N+1 corresponds to the cavity n = 1.[3] Note that the model exhibits quantum tunneling; this process is similar to the Josephson effect.[6][7]

Defining the photonic and atomic excitation number operators as and , the total number of excitations is a conserved quantity, i.e., .

Two-polariton bound states

The JCH Hamiltonian supports two-polariton bound states when the photon-atom interaction is sufficiently strong. In particular, the two polaritons associated with the bound states exhibit a strong correlation such that they stay close to each other in position space.[8] This process is similar to the formation of a bound pair of repulsive bosonic atoms in an optical lattice.[9][10][11]

Further reading

  • D. F. Walls and G. J. Milburn (1995), Quantum Optics, Springer-Verlag.

References

  1. Schmidt, S.; Blatter, G. (Aug 2009). "Strong Coupling Theory for the Jaynes-Cummings-Hubbard Model". Phys. Rev. Lett. 103 (8): 086403. arXiv:0905.3344. Bibcode:2009PhRvL.103h6403S. doi:10.1103/PhysRevLett.103.086403. PMID 19792743. S2CID 32092406.
  2. A. Nunnenkamp; Jens Koch; S. M. Girvin (2011). "Synthetic gauge fields and homodyne transmission in Jaynes-Cummings lattices". New Journal of Physics. 13 (9): 095008. arXiv:1105.1817. Bibcode:2011NJPh...13i5008N. doi:10.1088/1367-2630/13/9/095008. S2CID 118557639.
  3. D. G. Angelakis; M. F. Santos; S. Bose (2007). "Photon-blockade-induced Mott transitions and XY spin models in coupled cavity arrays". Physical Review A. 76 (3): 1805(R). arXiv:quant-ph/0606159. Bibcode:2007PhRvA..76c1805A. doi:10.1103/physreva.76.031805. S2CID 44490741.
  4. M. J. Hartmann, F. G. S. L. Brandão and M. B. Plenio (2006). "Strongly interacting polaritons in coupled arrays of cavities". Nature Physics. 2 (12): 849–855. arXiv:quant-ph/0606097. Bibcode:2006NatPh...2..849H. doi:10.1038/nphys462. S2CID 9122839.
  5. A. D. Greentree; C. Tahan; J. H. Cole; L. C. L. Hollenberg (2006). "Quantum phase transitions of light". Nature Physics. 2 (12): 856–861. arXiv:cond-mat/0609050. Bibcode:2006NatPh...2..856G. doi:10.1038/nphys466. S2CID 118903056.
  6. B. W. Petley (1971). An Introduction to the Josephson Effects. London: Mills and Boon.
  7. Antonio Barone; Gianfranco Paternó (1982). Physics and Applications of the Josephson Effect. New York: Wiley.
  8. Max T. C. Wong; C. K. Law (May 2011). "Two-polariton bound states in the Jaynes-Cummings-Hubbard model". Phys. Rev. A. American Physical Society. 83 (5): 055802. arXiv:1101.1366. Bibcode:2011PhRvA..83e5802W. doi:10.1103/PhysRevA.83.055802. S2CID 119200554.
  9. K. Winkler; G. Thalhammer; F. Lang; R. Grimm; J. H. Denschlag; A. J. Daley; A. Kantian; H. P. Buchler; P. Zoller (2006). "Repulsively bound atom pairs in an optical lattice". Nature. 441 (7095): 853–856. arXiv:cond-mat/0605196. Bibcode:2006Natur.441..853W. doi:10.1038/nature04918. PMID 16778884. S2CID 2214243.
  10. Javanainen, Juha and Odong, Otim and Sanders, Jerome C. (Apr 2010). "Dimer of two bosons in a one-dimensional optical lattice". Phys. Rev. A. 81 (4): 043609. arXiv:1004.5118. Bibcode:2010PhRvA..81d3609J. doi:10.1103/PhysRevA.81.043609. S2CID 55445588.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. M. Valiente; D. Petrosyan (2008). "Two-particle states in the Hubbard model". J. Phys. B: At. Mol. Opt. Phys. 41 (16): 161002. arXiv:0805.1812. Bibcode:2008JPhB...41p1002V. doi:10.1088/0953-4075/41/16/161002. S2CID 115168045.
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