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Theory of radiative electron polarization in strong laser fields

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Article number023417
<mark>Journal publication date</mark>20/08/2018
<mark>Journal</mark>Physical review a
Issue number2
Number of pages19
Publication StatusPublished
<mark>Original language</mark>English


Radiative polarization of electrons and positrons through the Sokolov-Ternov effect is important for applications in high-energy physics. Radiative spin polarization is a manifestation of quantum radiation reaction affecting the spin dynamics of electrons. We recently proposed that an analog of the Sokolov-Ternov effect could occur in the strong electromagnetic fields of ultra-high-intensity lasers, which would result in a buildup of spin polarization in femtoseconds. In this paper, we develop a density matrix formalism for describing beam polarization in strong electromagnetic fields. We start by using the density matrix formalism to study spin flips in nonlinear Compton scattering and its dependence on the initial polarization state of the electrons. Numerical calculations show a radial polarization of the scattered electron beam in a circularly polarized laser, and we find azimuthal asymmetries in the polarization patterns for ultrashort laser pulses. A degree of polarization approaching 9% is achieved after emitting just a single photon. We develop the theory by deriving a local constant crossed-field approximation (LCFA) for the polarization density matrix, which is a generalization of the well-known LCFA scattering rates. We find spin-dependent expressions that may be included in electromagnetic charged-particle simulation codes, such as particle-in-cell plasma simulation codes, using Monte Carlo modules. In particular, these expressions include the spin-flip rates for arbitrary initial polarization of the electrons. The validity of the LCFA is confirmed by explicit comparison with an exact QED calculation of electron polarization in an ultrashort laser pulse. © 2018 authors.

Bibliographic note

Funding details: Engineering and Physical Sciences Research Council, EPSRC, EP/M018156/1 Funding details: W911NF-16-1-0044 Funding details: Science and Technology Facilities Council, STFC, ST/G008248/1 Funding text 1: D.S. acknowledges valuable discussions with J. Gratus, T. Heinzl, A. Ilderton, B. King, and M. Korostelev, and support from the Science and Technology Facilities Council, Grant No. ST/G008248/1. C.P.R. and D.D.S. acknowledge support from Engineering and Physical Sciences Grant No. EP/M018156/1. A.G.R.T. acknowledges support from U. S. DOD under Grant No. W911NF-16-1-0044. APPENDIX A: References: Patrignani, C., The review of particle physics (2016) Chin. Phys. C, 40, p. 100001; David Jackson, J., (1983) Klassische Elektrodynamik, , 2nd ed. (Walter de Gruyter, Berlin); Anselmino, M., Efremov, A., Leader, E., The theory and phenomenology of polarized deep inelastic scattering (1995) Phys. Rep., 261, p. 1; Steven, D., Bass, The Proton Spin Puzzle: Where Are We Today? (2009) Mod. Phys. Lett. A, 24, p. 1087; Prescott, C.Y., Atwood, W.B., Cottrell, R.L.A., DeStaebler, H., Garwin, E.L., Gonidec, A., Miller, R.H., Jentschke, W., Parity non-conservation in inelastic electron scattering (1978) Phys. Lett. B, 77, p. 347; Labzowsky, L.N., Nefiodov, A.V., Plunien, G., Soff, G., Marrus, R., Liesen, D., Parity-violation effect in heliumlike gadolinium and europium (2001) Phys. Rev. A, 63, p. 054105; Vauth, A., List, J., Beam polarization at the ilc: Physics case and realization (2016) Int. J. Mod. Phys. Conf. Ser., 40, p. 1660003; Mane, S.R., Shatunov, Yu.M., Yokoya, K., Spin-polarized charged particle beams in high-energy accelerators (2005) Rep. Prog. Phys., 68, p. 1997; Subashiev, A.V., Mamaev, Yu.A., Yashin, Yu.P., Clendenin, J.E., Spin polarized electrons: Generation and applications (1999) Phys. Low-Dim. Struct., 1, p. 1; Mamaev, Yu.A., Gerchikov, L.G., Yashin, Yu.P., Vasiliev, D.A., Kuzmichev, V.V., Ustinov, V.M., Zhukov, A.E., Vasiliev, A.P., Optimized photocathode for spin-polarized electron sources (2008) Appl. Phys. Lett., 93, p. 081114; Sokolov, A.A., Ternov, I.M., (1968) Synchrotron Radiation, , (Akademie Verlag, Berlin); Ternov, I.M., Synchrotron radiation (1995) Phys. Usp., 38, p. 409; Esarey, E., Schroeder, C.B., Leemans, W.P., Physics of laser-driven plasma-based electron accelerators (2009) Rev. Mod. Phys., 81, p. 1229; Vieira, J., Huang, C.-K., Mori, W.B., Silva, L.O., Polarized beam conditioning in plasma based acceleration (2011) Phys. Rev. Spec. Top.-Accel. Beams, 14, p. 071303; Del Sorbo, D., Seipt, D., Blackburn, T.G., Thomas, A.G.R., Murphy, C.D., Kirk, J.G., Ridgers, C.P., Spin polarization of electrons by ultraintense lasers (2017) Phys. Rev. A, 96, p. 043407; Del Sorbo, D., Seipt, D., Thomas, R.A.G., Ridgers, C.P., Electron spin polarization in realistic trajectories around the magnetic node of two counter-propagating, circularly polarized, ultra-intense lasers (2018) Plasma Phys. Controlled Fusion, 60, p. 064003; Cole, J.M., Behm, K.T., Gerstmayr, E., Blackburn, T.G., Wood, J.C., Baird, C.D., Duff, M.J., Symes, D.R., Experimental Evidence of Radiation Reaction in the Collision of a High-Intensity Laser Pulse with a Laser-Wakefield Accelerated Electron Beam (2018) Phys. Rev. X, 8, p. 011020; Poder, K., Tamburini, M., Sarri, G., Di Piazza, A., Kuschel, S., Baird, C.D., Behm, K., Symes, D., Evidence of Strong Radiation Reaction in the Field of an Ultra-Intense Laser (2018) Phys. Rev. X, 8, p. 031004; Kirsebom, K., Mikkelsen, U., Uggerhøj, E., Elsener, K., Ballestrero, S., Sona, P., Vilakazi, Z.Z., First Measurements of the Unique Influence of Spin on the Energy Loss of Ultrarelativistic Electrons in Strong Electromagnetic Fields (2001) Phys. Rev. Lett., 87, p. 054801; Panek, P., Kamiński, J.Z., Ehlotzky, F., Laser-induced Compton scattering at relativistically high radiation powers (2002) Phys. Rev. A, 65, p. 022712; Dumlu, C.K., Dunne, G.V., Interference effects in Schwinger vacuum pair production for time-dependent laser pulses (2011) Phys. Rev. D, 83, p. 065028; Boca, M., Dinu, V., Florescu, V., Spin effects in nonlinear Compton scattering in a plane-wave laser pulse (2012) Nucl. Instruments Methods Phys. Res., Sect. B, 279, p. 12; Jansen, M.J.A., Kamiński, J.Z., Krajewska, K., Müller, C., Strong-field Breit-Wheeler pair production in short laser pulses: Relevance of spin effects (2016) Phys. Rev. D, 94, p. 013010; Bagrov, V.G., Fedosov, N.I., Kopytov, G.F., Oxsyzyan, S.S., Tlyachev, V.B., Radiational self-polarization of electrons moving in the electromagnetic plane-wave field (1989) Nuovo Cimento B Ser. 11, 103, p. 549; Bol'Shedvorsky, E., Polityko, S., Misaki, A., Spin of scattered electrons in the nonlinear Compton effect (2000) Prog. Theor. Phys., 104, p. 769; Bolshedvorsky, E.M., Polityko, S.I., Polarization of the final electron in the field of an intense electromagnetic wave (2000) Russ. Phys. J., 43, p. 913; Yu Ivanov, D., Kotkin, G.L., Serbo, V.G., Complete description of polarization effects in emission of a photon by an electron in the field of a strong laser wave (2004) Eur. Phys. J. C, 36, p. 127; Karlovets, D.V., Radiative polarization of electrons in a strong laser wave (2011) Phys. Rev. A, 84, p. 062116; Krajewska, K., Kamiński, J.Z., Spin effects in nonlinear Compton scattering in ultrashort linearly-polarized laser pulses (2013) Laser Part. Beams, 31, p. 503; Krajewska, K., Kamiński, J.Z., Frequency scaling law for nonlinear Compton and Thomson scattering: Relevance of spin and polarization effects (2014) Phys. Rev. A, 90, p. 052117; King, B., Elkina, N., Ruhl, H., Photon polarization in electron-seeded pair-creation cascades (2013) Phys. Rev. A, 87, p. 042117; King, B., Double Compton scattering in a constant crossed field (2015) Phys. Rev. A, 91, p. 033415; Meuren, S., Di Piazza, A., Quantum Electron Self-Interaction in a Strong Laser Field (2011) Phys. Rev. Lett., 107, p. 260401; Ahrens, S., Bauke, H., Keitel, C.H., Müller, C., Spin Dynamics in the Kapitza-Dirac Effect (2012) Phys. Rev. Lett., 109, p. 043601; Barth, I., Smirnova, O., Spin-polarized electrons produced by strong-field ionization (2013) Phys. Rev. A, 88, p. 013401; Klaiber, M., Hatsagortsyan, K.Z., Spin-asymmetric laser-driven relativistic tunneling from (Equation presented) states (2014) Phys. Rev. A, 90, p. 063416; Zille, D., Seipt, D., Möller, M., Fritzsche, S., Gräfe, S., Müller, C., Paulus, G.G., Spin-dependent rescattering in strong-field ionization of helium (2017) J. Phys. B: At., Mol. Opt. Phys., 50, p. 065001; Zille, D., Seipt, D., Möller, M., Fritzsche, S., Paulus, G.G., Milošević, D.B., Spin-dependent quantum theory of high-order above-threshold ionization (2017) Phys. Rev. A, 95, p. 063408; Dellweg, M.M., Müller, C., Controlling electron spin dynamics in bichromatic Kapitza-Dirac scattering by the laser field polarization (2017) Phys. Rev. A, 95, p. 042124; Nikishov, A.I., Ritus, V.I., Quantum processes in the field of a plane electromagnetic wave and in a constant field. i (1964) Zh. Eksp. Teor. Fiz., 46, p. 776; Nikishov, A.I., Ritus, V.I., (1964) Sov. Phys. JETP, 19, p. 529. , [, ()]; Nikishov, A.I., Ritus, V.I., Quantum processes in the field of a plane electromagnetic wave and in a constant field (1964) Zh. Eksp. Teor. Fiz., 46, p. 1768; Nikishov, A.I., Ritus, V.I., (1964) Sov. Phys. JETP, 19, p. 1191. , [, ()]; Goldman, I.I., Intensity effects in Compton scattering (1964) Phys. Lett., 8, p. 103; Brown, L.S., Kibble, T.W.B., Interaction of intense laser beams with electrons (1964) Phys. Rev., 133, p. A705; Nikishov, A.I., Ritus, V.I., Nonlinear effects in Compton scattering and pair production owing to absorption of several photons (1964) Zh. Eksp. Teor. Fiz., 47, p. 1130; Nikishov, A.I., Ritus, V.I., (1965) Sov. Phys. JETP, 20, p. 757. , [, ()]; Narozhnyi, N.B., Nikishov, A.I., Ritus, V.I., Quantum processes in the field of a circularly polarized electromagnetic wave (1964) Zh. Eksp. Teor. Fiz., 47, p. 930; Narozhnyi, N.B., Nikishov, A.I., Ritus, V.I., (1965) Sov. Phys. JETP, 20, p. 622. , [, ()]; Seipt, D., Kämpfer, B., Non-linear Compton scattering of ultrashort and intense laser pulses (2011) Phys. Rev. A, 83, p. 022101; Wolkow, D.M., Über eine Klasse von Lösungen der Diracschen Gleichung (1935) Z. Phys., 94, p. 250; Raicher, E., Eliezer, S., Analytical solutions of the Dirac and the Klein-Gordon equations in plasma induced by high-intensity laser (2013) Phys. Rev. A, 88, p. 022113; King, B., Hu, H., Classical and quantum dynamics of a charged scalar particle in a background of two counterpropagating plane waves (2016) Phys. Rev. D, 94, p. 125010; Heinzl, T., Ilderton, A., King, B., Classical and quantum particle dynamics in univariate background fields (2016) Phys. Rev. D, 94, p. 065039; Ilderton, A., Torgrimsson, G., Scattering in plane-wave backgrounds: Infrared effects and pole structure (2013) Phys. Rev. D, 87, p. 085040; Berestetskii, V., Lifshitz, E., Pitaevskii, L., (1982) Quantum Electrodynamics, , Course of Theoretical Physics, 4 (Butterworth, Washington, DC); Mitter, H., Quantum Electrodynamics in Laser Fields (1975) Acta Phys. Austriaca, Suppl. XIV, p. 397; Ritus, V.I., Quantum effects of the interaction of elementary particles with an intense electromagnetic field (1985) J. Sov. Laser Res., 6, p. 497; Harvey, C., Heinzl, T., Ilderton, A., Signatures of high-intensity Compton scattering (2009) Phys. Rev. A, 79, p. 063407; Seipt, D., Kharin, V., Rykovanov, S., Surzhykov, A., Fritzsche, S., Analytical results for nonlinear Compton scattering in short intense laser pulses (2016) J. Plasma Phys., 82, p. 655820203; Fradkin, D.M., Good, R.H., Electron polarization operators (1961) Rev. Mod. Phys., 33, p. 343; Bauke, H., Ahrens, S., Keitel, C.H., Grobe, R., Electron-spin dynamics induced by photon spins (2014) New J. Phys., 16, p. 103028; Bliokh, K.Y., Dennis, M.R., Nori, F., Position, spin, and orbital angular momentum of a relativistic electron (2017) Phys. Rev. A, 96, p. 023622; Itzykson, C., Zuber, J.-B., (1980) Quantum Field Theory, , (McGraw-Hill, New York); Lorcé, C., New explicit expressions for Dirac bilinears (2018) Phys. Rev. D, 97, p. 016005; Bargmann, V., Michel, L., Telegdi, V.L., Precession of the Polarization of Particles Moving in a Homogeneous Electromagnetic Field (1959) Phys. Rev. Lett., 2, p. 435; Spohn, H., Semiclassical limit of the Dirac equation and spin precession (2000) Ann. Phys. (NY), 282, p. 420; Bulanov, S.S., Schroeder, C.B., Esarey, E., Leemans, W.P., Electromagnetic cascade in high-energy electron, positron, and photon interactions with intense laser pulses (2013) Phys. Rev. A, 87, p. 062110; Blum, K., (2012) Density Matrix Theory and Applications, , 3rd ed., Springer Series on Atomic, Optical, and Plasma Physics, 64 (Springer, Berlin); Baier, V.N., Katkov, V.M., Strakhovenko, V.M., (1998) Electromagnetic Processes at High Energies in Oriented Single Crystals, , (World Scientific, Singapore); Balashov, V.V., Grum-Grzhimailo, A.N., Kabachnik, N.M., (2000) Polarization and Correlation Phenomena in Atomic Collisions, , (Springer, Berlin); Surzhykov, A., Fritzsche, S., Stöhlker, T., Effects of the target polarization on the diagnostics of spin-polarized heavy ions (2007) Radiat. Phys. Chem., 76, p. 392; Lötstedt, E., Jentschura, U.D., Nonperturbative Treatment of Double Compton Backscattering in Intense Laser Fields (2009) Phys. Rev. Lett., 103, p. 110404; Kämpfer, T., Uschmann, I., Wu, Z.W., Surzhykov, A., Fritzsche, S., Förster, E., Paulus, G.G., Linear polarization of the characteristic x-ray lines following inner-shell photoionization of tungsten (2016) Phys. Rev. A, 93, p. 033409; Peshkov, A.A., Seipt, D., Surzhykov, A., Fritzsche, S., Photoexcitation of atoms by Laguerre-Gaussian beams (2017) Phys. Rev. A, 96, p. 023407; Stock, S., Surzhykov, A., Fritzsche, S., Seipt, D., Compton scattering of twisted light: Angular distribution and polarization of scattered photons (2015) Phys. Rev. A, 92, p. 013401; Angioi, A., Mackenroth, F., Di Piazza, A., Nonlinear single Compton scattering of an electron wave packet (2016) Phys. Rev. A, 93, p. 052102; Thomas, A.G.R., Algorithm for calculating spectral intensity due to charged particles in arbitrary motion (2010) Phys. Rev. Spec. Top.-Accel. Beams, 13, p. 020702; Ahrens, S., Sun, C.-P., Spin in Compton scattering with pronounced polarization dynamics (2017) Phys. Rev. A, 96, p. 063407; Esarey, E., Ride, S.K., Sprangle, P., Nonlinear Thomson scattering of intense laser pulses from beams and plasmas (1993) Phys. Rev. e, 48, p. 3003; Kotkin, G.L., Serbo, V.G., Telnov, V.I., Electron (positron) beam polarization by Compton scattering on circularly polarized laser photons (2003) Phys. Rev. Spec. Top.-Accel. Beams, 6, p. 011001; Seipt, D., Kämpfer, B., Asymmetries of azimuthal photon distributions in nonlinear Compton scattering in ultrashort intense laser pulses (2013) Phys. Rev. A, 88, p. 012127; Titov, A.I., Kämpfer, B., Hosaka, A., Nousch, T., Seipt, D., Determination of the carrier envelope phase for short, circularly polarized laser pulses (2016) Phys. Rev. D, 93, p. 045010; Seipt, D., Kämpfer, B., Two-photon Compton process in pulsed intense laser fields (2012) Phys. Rev. D, 85, p. 101701; Ilderton, A., Torgrimsson, G., Radiation reaction from QED: Lightfront perturbation theory in a plane wave background (2013) Phys. Rev. D, 88, p. 025021; Dinu, V., Harvey, C., Ilderton, A., Marklund, M., Torgrimsson, G., Quantum Radiation Reaction: From Interference to Incoherence (2016) Phys. Rev. Lett., 116, p. 044801; Ridgers, C.P., Kirk, J.G., Duclous, R., Blackburn, T.G., Brady, C.S., Bennett, K., Arber, T.D., Bell, A.R., Modelling gamma-ray photon emission and pair production in high-intensity laser-matter interactions (2014) J. Comput. Phys., 260, p. 273; Gonoskov, A., Bastrakov, S., Efimenko, E., Ilderton, A., Marklund, M., Meyerov, I., Muraviev, A., Wallin, E., Extended particle-in-cell schemes for physics in ultrastrong laser fields: Review and developments (2015) Phys. Rev. e, 92, p. 023305; Green, D.G., Harvey, C.N., SIMLA: Simulating particle dynamics in intense laser and other electromagnetic fields via classical and quantum electrodynamics (2015) Comput. Phys. Commun., 192, p. 313; Harvey, C.N., Ilderton, A., King, B., Testing numerical implementations of strong-field electrodynamics (2015) Phys. Rev. A, 91, p. 013822; Blackburn, T.G., Seipt, D., Bulanov, S.S., Marklund, M., Benchmarking semiclassical approaches to strong-field QED: Nonlinear Compton scattering in intense laser pulses (2018) Phys. Plasmas, 25, p. 083108; Dinu, V., Exact final-state integrals for strong-field QED (2013) Phys. Rev. A, 87, p. 052101; Di Piazza, A., Tamburini, M., Meuren, S., Keitel, C.H., Implementing nonlinear Compton scattering beyond the local constant field approximation (2018) Phys. Rev. A, 98, p. 012134; Elkina, N.V., Fedotov, A.M., Yu Kostyukov, I., Legkov, M.V., Narozhny, N.B., Nerush, E.N., Ruhl, H., QED cascades induced by circularly polarized laser fields (2011) Phys. Rev. Spec. Top.-Accel. Beams, 14, p. 054401; Milošević, D.B., Paulus, G.G., Bauer, D., Becker, W., Above-threshold ionization by few-cycle pulses (2006) J. Phys. B: At., Mol. Opt. Phys., 39, p. R203; Baier, V.N., Katkov, V.M., Radiative Polarization of Electrons in a Magnetic Field (1967) Zh. Eksp. Teor. Fiz., 52, p. 1422; Baier, V.N., Katkov, V.M., (1967) Sov. Phys. JETP, 25, p. 944. , [, ()]; Ritus, V.I., Radiative corrections in quantum electrodynamics with intense field and their analytical properties (1972) Ann. Phys. (NY), 69, p. 555; Kibble, T.W.B., Salam, A., Strathdee, J., Intensity-dependent mass shift and symmetry breaking (1975) Nucl. Phys. B, 96, p. 255; Harvey, C., Heinzl, T., Ilderton, A., Marklund, M., The Intensity Dependent Mass Shift: Existence, Universality and Detection (2012) Phys. Rev. Lett., 109, p. 100402; Di Piazza, A., Completeness and orthonormality of the Volkov states and the Volkov propagator in configuration space (2018) Phys. Rev. D, 97, p. 056028; Hebenstreit, F., Ilderton, A., Marklund, M., Zamanian, J., Strong field effects in laser pulses: The Wigner formalism (2011) Phys. Rev. D, 83, p. 065007