Abstract
We start with a general theoretical introduction to \(\mathcal {PT}\)-symmetric systems. Quantum systems with gain and loss can be modeled by non-Hermitian Hamiltonians, and \(\mathcal {PT}\)-symmetry is a property that can be achieved, e.g. by a coupling with the laser field. The resulting \(\mathcal {PT}\)-symmetric Hamiltonians possess a real spectrum (when the gain and loss are not too strong) and can be considered as a special case of pseudo-Hermitian Hamiltonians. The transition from a real to a complex spectrum occurs at the exceptional point (EP), where two eigenmodes coalesce both in eigenvalue and eigenvector. The \(\mathcal {PT}\)-symmetric Hamiltonian can be realized experimentally in a system of two coupled waveguides with loss and gain. We describe in detail two physical effects related to the EPs in such a system. First, we show that light oscillations between two waveguides are suppressed by approaching the EP condition. Second, we prove that the group velocity of a light pulse decreases to zero as the system is tuned to be at the EP.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Agrawal, G.P.: Nonlinear Fiber Optics. Academic, Amsterdam (2013)
Arnold, V.I.: Geometrical Methods in the Theory of Ordinary Differential Equations. Springer Science & Business Media, New York (2012)
Baba, T.: Slow light in photonic crystals. Nat. Photonics 2(8), 465–473 (2008)
Bajcsy, M., Zibrov, A.S., Lukin, M.D.: Stationary pulses of light in an atomic medium. Nature 426(6967), 638–641 (2003)
Bender, C.M.: Making sense of non-Hermitian Hamiltonians. Rep. Prog. Phys. 70(6), 947 (2007)
Bender, C.M., Boettcher, S.: Real spectra in non-Hermitian Hamiltonians having PT symmetry. Phys. Rev. Lett. 80(24), 5243 (1998)
Bender, C.M., Berry, M.V., Mandilara, A.: Generalized PT symmetry and real spectra. J. Phys. A 35(31), L467 (2002)
Berry, M.V., Dennis, M.R.: The optical singularities of birefringent dichroic chiral crystals. Proc. R. Soc. A 459(2033), 1261–1292 (2003)
Boyd, R.W., Gauthier, D.J.: Controlling the velocity of light pulses. Science 326(5956), 1074–1077 (2009)
Cham, J.: Top 10 physics discoveries of the last 10 years. Nat. Phys. 11(10), 799 (2015)
Dembowski, C., Gräf, H.D., Harney, H.L., Heine, A., Heiss, W.D., Rehfeld, H., Richter, A.: Experimental observation of the topological structure of exceptional points. Phys. Rev. Lett. 86(5), 787–790 (2001)
Doppler, J., Mailybaev, A.A., Böhm, J., Kuhl, U., Girschik, A., Libisch, F., Milburn, T.J., Rabl, P., Moiseyev, N., Rotter, S.: Dynamically encircling an exceptional point for asymmetric mode switching. Nature 537(7618), 76–79 (2016)
El-Ganainy, R., Makris, K.G., Christodoulides, D.N., Musslimani, Z.H.: Theory of coupled optical PT-symmetric structures. Opt. Lett. 32(17), 2632–2634 (2007)
El-Ganainy, R., Makris, K.G., Khajavikhan, M., Musslimani, Z.H., Rotter, S., Christodoulides, D.N.: Non-Hermitian physics and PT symmetry. Nat. Phys. 14(1), 11 (2018)
Ge, L., Türeci, H.E.: Antisymmetric PT-photonic structures with balanced positive-and negative-index materials. Phys. Rev. A 88(5), 053810 (2013)
Gilary, I., Moiseyev, N.: Asymmetric effect of slowly varying chirped laser pulses on the adiabatic state exchange of a molecule. J. Phys. B 45(5), 051002 (2012)
Gilary, I., Mailybaev, A.A., Moiseyev, N.: Time-asymmetric quantum-state-exchange mechanism. Phys. Rev. A 88(1), 010102 (2013)
Goldzak, T., Mailybaev, A.A., Moiseyev, N.: Light stops at exceptional points. Phys. Rev. Lett. 120, 013901 (2018)
Hau, L.V., Harris, S.E., Dutton, Z., Behroozi, C.H.: Light speed reduction to 17 metres per second in an ultracold atomic gas. Nature 397(6720), 594–598 (1999)
Jackson, J.D.: Classical Electrodynamics. Wiley, Chichester (1999)
Klaiman, S., Günther, U., Moiseyev, N.: Visualization of branch points in PT-symmetric waveguides. Phys. Rev. Lett. 101(8), 080402 (2008)
Kottos, T.: Optical physics: broken symmetry makes light work. Nat. Phys. 6(3), 166–167 (2010)
Landau, L.D., Lifshitz, E.M.: Quantum Mechanics, Non-relativistic Theory. Pergamon, Oxford (1991)
Mailybaev, A.A.: Computation of multiple eigenvalues and generalized eigenvectors for matrices dependent on parameters. Numer. Linear Algebra Appl. 13(5), 419–436 (2006)
Moiseyev, N.: Non-Hermitian Quantum Mechanics. Cambridge University Press, Cambridge/New York (2011)
Moiseyev, N., Friedland, S.: Association of resonance states with the incomplete spectrum of finite complex-scaled Hamiltonian matrices. Phys. Rev. A 22(2), 618–624 (1980)
Mostafazadeh, A.: Pseudo-Hermiticity versus PT symmetry: the necessary condition for the reality of the spectrum of a non-Hermitian Hamiltonian. J. Math. Phys. 43(1), 205–214 (2002)
Mostafazadeh, A.: Quantum brachistochrone problem and the geometry of the state space in pseudo-Hermitian quantum mechanics. Phys. Rev. Lett. 99(13), 130502 (2007)
Peng, P., Cao, W., Shen, C., Qu, W., Wen, J., Jiang, L., Xiao, Y.: Anti-parity-time symmetry with flying atoms. Nat. Phys. 12(12), 1139–1145 (2016)
Ruschhaupt, A., Delgado, F., Muga, J.G.: Physical realization of-symmetric potential scattering in a planar slab waveguide. J. Phys. A 38(9), L171–L176 (2005)
Rüter, C.E., Makris, K.G., El-Ganainy, R., Christodoulides, D.N., Segev, M., Kip, D.: Observation of parity–time symmetry in optics. Nat. Phys. 6(3), 192–195 (2010)
Schomerus, H., Wiersig, J.: Non-Hermitian-transport effects in coupled-resonator optical waveguides. Phys. Rev. A 90(5), 053819 (2014)
Seyranian, A.P., Mailybaev, A.A.: Multiparameter stability theory with mechanical applications. World Scientific, Singapore (2003)
Seyranian, A.P., Kirillov, O.N., Mailybaev, A.A.: Coupling of eigenvalues of complex matrices at diabolic and exceptional points. J. Phys. A 38(8), 1723–1740 (2005)
Siegman, A.E.: Propagating modes in gain-guided optical fibers. J. Opt. Soc. Am. A 20(8), 1617–1628 (2003)
Tanaka, Y., Upham, J., Nagashima, T., Sugiya, T., Asano, T., Noda, S.: Dynamic control of the Q factor in a photonic crystal nanocavity. Nat. Mater. 6(11), 862–865 (2007)
Uzdin, R., Mailybaev, A.A., Moiseyev, N.: On the observability and asymmetry of adiabatic state flips generated by exceptional points. J. Phys. A 44(43), 435302 (2011)
Wang, L.J., Kuzmich, A., Dogariu, A.: Gain-assisted superluminal light propagation. Nature 406(6793), 277–279 (2000)
Weiner, A.: Ultrafast Optics. Wiley, New York (2011)
Wigner, E.: On a modification of the Rayleigh–Schrdinger perturbation theory. Math. Natur. Anz. (Budapest) 53, 477–482 (1935)
Withayachumnankul, W., Fischer, B.M., Ferguson, B., Davis, B.R., Abbott, D.: A systemized view of superluminal wave propagation. Proc. IEEE 98(10), 1775–1786 (2010)
Wu, J.H., Artoni, M., La Rocca, G.C.: Parity-time-antisymmetric atomic lattices without gain. Phys. Rev. A 91(3), 033811 (2015)
Xu, H., Mason, D., Jiang, L., Harris, J.G.E.: Topological energy transfer in an optomechanical system with exceptional points. Nature 537(7618), 80–83 (2016)
Yanik, M.F., Suh, W., Wang, Z., Fan, S.: Stopping light in a waveguide with an all-optical analog of electromagnetically induced transparency. Phys. Rev. Lett. 93(23), 233903 (2004)
Acknowledgements
The authors thank Adi Pick for most helpful comments. N.M. acknowledges the financial support of I-Core: The Israeli Excellence Center “Circle of Light”, and of the Israel Science Foundation Grant No. 1530/15. A.A.M. was supported by the CNPq Grant No. 302351/2015-9.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2018 Springer Nature Singapore Pte Ltd.
About this chapter
Cite this chapter
Moiseyev, N., Mailybaev, A.A. (2018). Effects of Exceptional Points in PT-Symmetric Waveguides. In: Christodoulides, D., Yang, J. (eds) Parity-time Symmetry and Its Applications. Springer Tracts in Modern Physics, vol 280. Springer, Singapore. https://doi.org/10.1007/978-981-13-1247-2_9
Download citation
DOI: https://doi.org/10.1007/978-981-13-1247-2_9
Published:
Publisher Name: Springer, Singapore
Print ISBN: 978-981-13-1246-5
Online ISBN: 978-981-13-1247-2
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)