Fortschr. Phys. 51, No. 4–5 (2003) 485 C Resonance and anti-resonance For the<strong>phase</strong><strong>space</strong>analysis <strong>of</strong> theresonanceweneed to evalu<strong>at</strong>ethesum ≡ ∞ Sl−r(κ; x)Sr(κ ′ ; x). (30) W (+) l r=−∞ <strong>The</strong>anti-resonance<strong>in</strong>volves thesum ≡ ∞ Sl−r(κ; x)Sr(κ; x + rπ). (31) W (−) l r=−∞ Westart our discussion with thesum W (−) l and first show th<strong>at</strong> it is closely rel<strong>at</strong>ed to the sum W (+) l .For this purposewe<strong>in</strong>troducethenew <strong>in</strong>tegr<strong>at</strong>ion variable¯y ≡−y <strong>in</strong> the expansion coefficient which yields Sr(κ; x) ≡ 1 π 2π −π Sr(κ; x + rπ) = 1 π 2π dy e iry −iκ[V (x+y)−V (x−y)] e −π d¯y e i(−r)¯y e −iκ[V (x+rπ−¯y)−V (x+rπ+¯y)] . Due to the periodicity properties V (x +2mπ) =V (x) and V (x +(2m +1)π) =−V (x) <strong>of</strong> thepotential wef<strong>in</strong>d thesymmetry rel<strong>at</strong>ion Sr(κ; x + rπ) =S−r(κ; x) which br<strong>in</strong>gs thesum W (−) l W (−) l = ∞ r=−∞ <strong>in</strong>to theform Sl−r(κ; x)S−r(κ; x). It is therefore convenient to evalu<strong>at</strong>e the sums ≡ ∞ Sl−r(κ; x)S±r(κ ′ ; x). C (±) l r=−∞ For this purposewesubstitutethedef<strong>in</strong>ition <strong>of</strong> Sr, Eq. (32), <strong>in</strong>to thesum and <strong>in</strong>terchangethesumm<strong>at</strong>ion and <strong>in</strong>tegr<strong>at</strong>ion which leads to C (±) l 1 = 4π2 π −π dy π −π dy ′ r e −ir(y∓y′ ) e ily e −i[κV(x,y)+κ′ V(x,y ′ )] . <strong>The</strong> sum <strong>in</strong> the curly brackets represents a comb <strong>of</strong> delta functions, Eq. (29), which allows us to perform the<strong>in</strong>tegral over y ′ , th<strong>at</strong> is C (±) l 1 = 2π π −π (32) dy e ily e −i(κ±κ′ )V(x,y) = Sl(κ ± κ ′ ; x). (33)
486 M. Bienert et al.: <strong>Kicked</strong> <strong>rotor</strong> <strong>in</strong> <strong>Wigner</strong> <strong>phase</strong> <strong>space</strong> Herewehaveused thesymmetry V(x, −y) =−V(x, y) follow<strong>in</strong>g from thedef<strong>in</strong>ition, Eq. (14), <strong>of</strong> V. Hence, <strong>in</strong> the sum W (+) l def<strong>in</strong>ed <strong>in</strong> Eq. (30) for a resonance the parameters κ and κ ′ add. At an antiresonancethesum W (−) l , Eq. (31), conta<strong>in</strong>s only thes<strong>in</strong>gleparameter κ. S<strong>in</strong>cethedifference<strong>of</strong> κ and κ ′ = κ appears <strong>in</strong> the explicit expression, Eq. (33), for C (−) l wef<strong>in</strong>d W (−) l = Sl(0; x) = 1 π 2π −π where δl,0 denotes the Kronecker-delta. dy e ily = δn,0 Acknowledgements We thank I. Sh. Averbukh, B. G. Englert, S. Fishman, M. Freyberger, H. J. Korsch and Th. Seligman for many fruitful discussions. This work orig<strong>in</strong><strong>at</strong>ed when two <strong>of</strong> us (FH and WPS) were enjoy<strong>in</strong>g the wonderful hospitality <strong>of</strong> the <strong>University</strong> <strong>of</strong> <strong>Texas</strong> <strong>at</strong> Aust<strong>in</strong>. We thank our Texan colleagues, <strong>in</strong> particular D. Steck, for many stimul<strong>at</strong><strong>in</strong>g discussions dur<strong>in</strong>g this visit. Moreover, we are most gr<strong>at</strong>eful to F. DeMart<strong>in</strong>i and P. M<strong>at</strong>aloni for p<strong>at</strong>iently await<strong>in</strong>g the completion <strong>of</strong> this manuscript. <strong>The</strong> work <strong>of</strong> MB and WPS is supported by the Deutsche Forschungsgeme<strong>in</strong>schaft. MGR gr<strong>at</strong>efully acknowledges the support <strong>of</strong> the Welch Found<strong>at</strong>ion and the N<strong>at</strong>ional Science Found<strong>at</strong>ion. References [1] F. Haake, Quantum Sign<strong>at</strong>ures <strong>of</strong> Chaos (Spr<strong>in</strong>ger, Heidelberg, 2000). [2] R. Blümel and W. P. Re<strong>in</strong>hardt, Chaos <strong>in</strong> Atomic Physics (Cambridge <strong>University</strong> Press, Cambridge, 1997). [3] V. V. Sokolov, O. V. Zhirov, D. Alonso, and G. Cas<strong>at</strong>i, Phys. Rev. Lett. 84, 3566 (2000), and references there<strong>in</strong>. [4] A. P. Kazantsev, G. I. Surdutovich, and V. P. Yakovlev, Mechanical Action <strong>of</strong> Light on Atoms (World Scientific, S<strong>in</strong>gapore, 1990). [5] C. S. Adams, M. Sigel, and J. Mlynek, Phys. Rep. 240, 143 (1994). [6] F. L. Moore, J. C. Rob<strong>in</strong>son, C. F. Bharucha, Bala Sundaram, and M. G. Raizen, Phys. Rev. Lett. 75, 4598 (1995). [7] F. L. Moore, J. C. Rob<strong>in</strong>son, C. Bharucha, P. E. Williams, and M. G. Raizen, Phys. Rev. Lett. 73, 2974 (1994). [8] M. G. Raizen, Adv. At. Mol. Opt. Phys. 41, 43 (1999), [9] A. C. Doherty, K. M.D. Vant, G. H. Ball, N. Christensen, and R. Leonhardt, J. Opt. B: Quantum Semiclass. Opt. 2, 605 (2000), [10] M. B. d’Arcy, R. M. Godun, M. K. Oberthaler, D. Cassettari, and G. S. Summy, Phys. Rev. Lett. 87, 074102 (2001). [11] M. Bienert, F. Haug, W. P. Schleich, and M. G. Raizen , Phys. Rev. Lett. 89, 050403 (2002). [12] W. P. Schleich, Quantum Optics <strong>in</strong> PhaseSpace(Wiley-VCH, Berl<strong>in</strong>, 2001). [13] H. J. Korsch and M. V. Berry, Physica 3D, 627 (1981). [14] D. Cohen, Phys. Rev. A 43, 639 (1991). [15] W. H. Zurek, Physica Scripta T 76, 186 (1998). [16] S. Habib, K. Shizume, and W. H. Zurek, Phys. Rev. Lett. 80, 4361 (1998). [17] S. A. Gard<strong>in</strong>er, D. Jaksch, R. Dum, J. I. Cirac, and P. Zoller, Phys. Rev. A 62, 023612 (2000). [18] W. P. Schleich, F. Le Kien, and M. Pernigo, Phys. Rev. A 44, 2172 (1991). [19] F. M. Izrailev, Phys. Rep. 196, 299 (1990). [20] L. E. Reichl, <strong>The</strong> Transition to Chaos (Spr<strong>in</strong>ger, Berl<strong>in</strong>, 1992). [21] M. Bienert, F. Haug, W. P. Schleich, and T. H. Seligman, to be published.