Addition theorems and the Drach superintegrable systems

We propose new construction of the polynomial integrals of motion related to the addition theorems. As an example we reconstruct Drach systems and get some new two-dimensional superintegrable Stackel systems with third, fifth and seventh order integr…

Authors: A. V. Tsiganov

Addition theorems and the Dr ac h sup erin tegrable systems A V Tsig anov St.Petersbur g State University, St.Petersbur g, Russia e–mail: tsiganov@mph.ph ys.spbu.ru Abstract W e pr op ose new construction of the p olynomial int egrals of mot ion rela ted to the addition theorems. As an example w e reconstruct Drac h systems and get some new tw o-dimensional s u p erintegrable St¨ ac k el systems with third, fifth and sev en th order integ rals of motion. P A CS n umb ers: 0 2.30.Jr, 02.30.Ik, 03.65.Fd Mathematics Sub ject Classification: 7 0H06, 70H20, 35Q72 1 In tro duction The Liouville classic al theorem o n completely in tegrable Hamilto nian systems implies that almost all p oints of the manifold M a re co v ered by a system o f op en t oroidal domains with the action-angle co ordinates I = ( I 1 , . . . , I k ) and ω = ( ω 1 , . . . , ω n ): { I j , I k } = { ω i , ω k } = 0 , { I j , ω k } = δ ij . (1.1) The independen t in tegrals of motion H 1 , . . . , H n are functions of the indep enden t action v ariables I 1 , . . . , I n and the corresp onding Jacobian do es not equal to zero det J 6 = 0 , where J ij = ∂ H i ( I 1 , . . . , I n ) ∂ I j . (1.2) Let us in tro duce n functions φ j = X k  J − 1  k j ω k , (1.3) suc h that { H i , φ j } = n X k =1 J ik  J − 1  k j = δ ij . (1.4) If Hamiltonian H = H 1 then the ( n − 1) functions φ 2 , . . . , φ n are in tegrals of mot ion dφ j dt = { H 1 , φ j } = 0 , j = 2 , . . . , n, 1 whic h are functionally indep enden t on n functions H 1 ( I ) , . . . , H n ( I ). So, in classical mec hanics an y completely integrable system is sup erin tegrable system in a neigh b orho o d of an y regular p oin t of M [14]. It means that the Hamiltonian H = H 1 has 2( n − 1) integrals of motion H 2 , . . . , H n and φ 2 , . . . , φ n on a ny op en toroidal domain. If the action-angle v ariables are global v ariables o n the whole phase space M and, therefore, w e ha v e sup erin tegrable systems o n M . F or instance, the global action-angle v ariables for the op en and p erio dic T o da lat t ices are discussed in [3]. Ho w ev er, in g eneric case the angle v ariables ω k are multi-v alued functions on the whole pha se space M . If w e ha v e k a dditio nal single-v alued algebraic inte gra ls of motion K t he tra jectories a re closed (more generally , t hey a re constrained to an n − k dimensional manifold in phase space). An y additional in tegral is a function on the actio n- angle v ariables. Since we hav e to understand ho w to get single-v alued additional inte gra ls of motio n from the m ulti- v alued action-a ngle v ariables. In this pap er we discuss a p ossibilit y to get p o lynomial in tegrals of mot io n from the m ulti-v alued angle v ariables by using simplest addition theorem. 2 The St¨ ac k e l systems. The system asso ciated with the name of St¨ ac k el [9, 10] is a holonomic system on the phase space M = R 2 n , with the canonical v a riables q = ( q 1 , . . . , q n ) and p = ( p 1 , . . . , p n ): Ω = n X j =1 dp j ∧ dq j , { p j , q k } = δ j k . (2.1) The nondegenerate n × n St¨ ac k el matrix S , whose j column dep ends on t he co ordinate q j only , defines n functionally indep enden t in tegrals of motion H k = n X j =1 ( S − 1 ) j k  p 2 j + U j ( q j )  . (2.2) F rom this definition one immediately gets the separated relations p 2 j = n X k =1 H k S k j − U j ( q j ) (2.3) and the angle v a riables ω i = X j =1 Z S ij d q j p j = X j =1 Z S ij d q j p P n k =1 H k S k j − U j ( q j ) . It allow s reducing solution of the equations of motion to a problem in algebraic geom- etry [10]. Namely , let us supp ose that there are functions µ j and λ j on the canonical separated v ariables µ j = u j ( q j ) p j , λ j = v j ( q j ) , { q i , p j } = δ ij , (2.4) 2 whic h allows us to rewrite separated equations (2.3) a s equations defining the h yp erel- liptic curv es C j : µ 2 j = P j ( λ j ) ≡ u 2 j ( λ j ) n X k =1 H k S k j ( λ j ) − U j ( λ j ) ! , (2.5) where P j ( λ j ) a r e polynomials on λ j . In this case the action v ariables I k = H k (2.2) ha v e the canonical P oisson brac k ets (1.1) with the angle v ariables ω i = n X j =1 Z A j S ij ( λ j ) p P j ( λ j ) d λ j = n X j =1 ϑ ij ( p j , q j ) , (2.6) whic h are the sums of in tegrals ϑ ij of the first kind Ab elian differen tials on the hyper- elliptic curv es C j (2.5) [10 , 14], i.e. they are sums of the mu lti- v alued functions o n the whole phase space. 2.1 Addition theorems and algebrai cally sup erin tegrable sys- tems In g eneric case the action v a riables (2 .6) ar e the sum of the m ulti-v alued functions ϑ ij . Ho w ev er, if w e are able to apply some additio n theorem to the calculation of ω i (2.6) ω i = n X j =1 ϑ ij ( p j , q j ) = Θ i  K i  + const, (2.7) where Θ i is a multi-v alued func tio n on the algebraic argument K i ( p, q ) then one will get algebraic in tegrals of motion K i ( p, q ) b ecause { H 1 , ω i } = { H 1 , Θ i  K i  } = Θ ′ i · { H 1 , K i } = 0 . So, the addition theorems (2.7) could help us to classify algebraically sup erintegrable systems a nd vice vers a. Plane curve s with the gen us g ≥ 1 are related to elliptic and Ab elian inte gra ls. Additio n theorems of these functions are the con tent of Ab el’s theorem [15]. The main result of this paper is that almost all the kno wn examples of algebraically sup erin tegrable system s relate with the one of the simplest addition theorem e x e y = e x + y , or ln( x 1 ) + ln( x 2 ) = ln ( x 1 x 2 ) (2.8) asso ciated with the zero-gen us h yp erelliptic curv es C j C j : µ 2 j = P j ( λ j ) = f j λ 2 j + g j λ j + h j , j = 1 , . . . , n, (2.9) where f j , g j , h j are linear functions o n n integrals of motio n H 1 , . . . , H n . In f a ct, if S ij ( λ ) = 1 then after substitution (2 .9) into (2.6) one g ets the sum of the rational functions ϑ j = Z 1 p g j λ j + h j d λ j = µ j g j 3 or logarithmic functions ϑ j = Z 1 q f j λ 2 j + g j λ j + h j d λ = f − 1 / 2 j ln µ j + 2 f j λ j + g j 2 p f j ! . F or the h yp erelliptic curv es of higher gen us one g ets elliptic functions, whic h ha v e more complicated addition la w [15]. In order to use addition low (2.8) w e hav e to mak e the follo wing steps: • W e hav e to apply canonical transformatio n o f the time that reduce n -th row of the St¨ ac k el matrix to the canonical Brill-No ether form [11, 13] S nj = 1 , j = 1 , . . . n , suc h that ω n = 1 N n X j =1 Z v j ( q j ) 1 p f j λ 2 + g j λ + h j d λ, (2.10) where N is norma lizat io n, whic h is restored from { ω n , H n } = 1 . • Then we hav e to use addition la w (2.8) for construction of the p olynomial in momen ta integrals of motion • W e ha ve to mak e inv erse transformation of the time, whic h preserv es the p o lyno- mial form of integrals suc h us it dep ends on q v ariables only [1 1, 13]. Let us consider construction of p olynomial in the momen ta integrals of motion at n = 2 . 2.1.1 Case f 1 = f 2 = 0 If f 1 , 2 = 0 w e ha v e ω 2 = 1 4 2 X j =1 Z v j ( q j ) 1 p g j λ + h j d λ = p 1 u 1 g 1 + p 2 u 2 g 2 = K g 1 g 2 , (2.11) where K = g 2 p 1 u 1 + g 1 p 2 u 2 is the p olynomial in the momen ta inte gra l of motion of the first or the t hird order. Remind that g 1 , 2 are linear f unctions on the St¨ ack el in tegrals H 1 , 2 , whic h are the sec ond order p olynomials on p 1 , 2 . Example 1 Let us consid er the t w o-dimensional St¨ ac k el system defined b y t w o Rie- mann surfaces C 1 , 2 : µ 2 = P 1 , 2 ( λ ) = ( H 1 ± H 2 ) λ + α 1 , 2 , and substitutions (2.4 ) µ j = q j p j , λ j = q 2 j , 4 whic h give rise to the following separated equations p 2 1 , 2 = H 1 ± H 2 + α 1 , 2 q 2 1 , 2 . In tegrals of mot ion H 1 and H 2 are solutions of these separated equations H 1 , 2 = p 2 1 ± p 2 2 2 − α 1 2 q 2 1 ∓ α 2 2 q 2 2 , (2.12) whic h coincide with in tegrals of motion fo r the t w o- particle Calogero system after an ob vious p oin t tra nsformation x = q 1 − q 2 2 , p x = p 1 − p 2 , y = q 1 + q 2 2 , p y = p 1 + p 2 . (2.13) The angle v aria bles (2.11) read as ω 1 , 2 = 1 4 Z q 2 1 1 p ( H 1 + H 2 ) λ + α 1 d λ ± 1 4 Z q 2 2 1 p ( H 1 − H 2 ) λ + α 2 d λ = − p 1 q 1 ( H 1 − H 2 ) ∓ p 2 q 2 ( H 1 + H 2 ) 2( H 1 + H 2 )( H 1 − H 2 ) . The corresp onding cubic in tegral o f motion K (2.11) is equal t o K = 2( H 1 + H 2 )( H 1 − H 2 ) ω 2 = − p 1 q 1 ( H 1 − H 2 ) + p 2 q 2 ( H 1 + H 2 ) . The brac ket { K , H 2 } = 2( H 2 2 − H 2 1 ) is easily restored from the canonical brac ke ts (1.1). 2.1.2 Case f 1 = k 2 1 f and f 2 = k 2 2 f with in teger k 1 , 2 In this case, we hav e ω 2 = 1 2 2 X j =1 Z v j ( q j ) 1 p f j λ 2 + g j λ + h j d λ = 2 X j =1 1 2 k j √ f ln  P ′ j 2 k j √ f + p j u j  , = 1 2 k 1 k 2 √ f ln "  P ′ 1 2 k 1 √ f + p 1 u 1  k 2  P ′ 2 2 k 2 √ f + p 2 u 2  k 1 # , where P ′ j = dP j ( λ ) dλ     λ = v j ( q j ) = 2 f j v j ( q j ) + g j . So function Φ 2 = exp(2 k 1 k 2 p f ω 2 ) =  P ′ 1 2 k 1 √ f + p 1 u 1  k 2  P ′ 2 2 k 2 √ f + p 2 u 2  k 1 = = 1 f ( k 1 + k 2 ) / 2  K ℓ + p f K m  (2.14) 5 is the generating function of p olynomial in tegrals of motion K m and K ℓ of the m -th and ℓ -th order, respectiv ely . The v alues of m and ℓ dep end on v alues of k 1 , 2 . As ab o v e, the algebra of integrals H 1 , 2 and K m ma y b e restored from the canonical brac k ets (1.1). Example 2 Let us consider the t w o- dimensional St¨ ac k el system defined b y the t w o Riemann surfaces C 1 , 2 : µ 2 1 , 2 = P 1 , 2 ( λ 1 , 2 ) = k 2 1 , 2 λ 2 1 , 2 + β 1 , 2 λ 1 , 2 + ( H 1 ± H 2 ) and substitutions (2.4 ) µ j = p j , λ j = q j , whic h give rise to the following separated equations p 2 1 , 2 = k 2 1 , 2 q 2 1 , 2 + β 1 , 2 q 1 , 2 + ( H 1 ± H 2 ) . In tegrals of mot ion H 1 and H 2 are solutions of these separated equations H 1 , 2 = p 2 1 ± p 2 2 2 − k 2 1 q 2 1 ± k 2 2 q 2 2 2 − β 1 q 1 ± β 2 q 2 2 , (2.15) whic h coincide with in tegrals of motion for t he harmonic o scillator. The same St¨ ac k el system coincides with the Kepler problem after w ell-known canonical transformation of the time, whic h c hanges the row o f t he St¨ ac ke l matrix [11]. The angle v ariable (2.11) reads as ω 2 = − 1 2 Z q j 1 p k 2 1 λ 2 + β 1 λ + ( H 1 + H 2 ) d λ − Z q 2 1 p k 2 2 λ 2 + β 2 λ + ( H 1 − H 2 ) d λ ! = = 1 2 p k 2 1 k 2 2 " q k 2 2 ln p 1 + P ′ 1 2 p k 2 1 ! − q k 2 1 ln p 2 + P ′ 2 2 p k 2 2 !# . Using suitable branches of q k 2 1 , one gets function (2 .14) Φ = exp(2 k 1 k 2 ω 2 ) =  p 1 − 2 k 2 1 q 1 + β 1 2 k 1  k 2  p 2 + 2 k 2 2 q 2 + β 2 2 k 2  k 1 , whic h generates p olynomial in tegrals of motion K m and K ℓ . As an example, if k 1 = 1 and k 2 = 3 one gets third and fourth order in tegrals of motion K m and K ℓ resp ectiv ely . Of course, oscillator is one of the well-studie d superintegrable systems, whic h was earmark ed to illustrate generic construction only . Additional theorem (2.8 ) a llo ws us to get a h uge family of the n - dimensional sup erin tegrable systems , whic h ha v e to b e classified and studied. 6 2.2 Classification In o rder to classify sup erin tegrable system s a sso ciated with the addition theorem (2.8) w e hav e to start with a pair o f the Riemann surfaces C j : µ 2 = P j ( λ ) = f λ 2 + g j λ + h j , j = 1 , 2 , (2.16) where f = α H 1 + β H 2 + γ , g j = α g j H 1 + β g j H 2 + γ g j , h j = α h j H 1 + β h j H 2 + γ h j , and α , β and γ are real or complex n umbers. In order to use addition theorem (2.8 ) we fix last row of the St¨ ac k el matrix. Namely , substituting S 2 j ( λ ) = κ j (2.17) in to the (2.3-2.6) one gets ϑ 2 j = Z S 2 j ( q j ) d q j p j = Z κ j d λ j p P j = κ j f − 1 / 2 ln  µ j + 2 f λ j + g j 2 √ f  , (2.18) so the angle v ar iable ω 2 = 1 √ f ln  p 1 u 1 + P ′ 1 2 √ f  κ 1  p 2 u 2 + P ′ 2 2 √ f  κ 2  , P ′ j = dP j ( λ ) dλ     λ = v j ( q j ) , is the m ulti-v alued function on the desired algebraic argument K =  p 1 u 1 + P ′ 1 2 √ f  κ 1  p 2 u 2 + P ′ 2 2 √ f  κ 2 . If κ 1 , 2 are p ositiv e in teger, then K =  1 2 √ f  κ 1 + κ 2  K ℓ + p f K m  (2.19) is the generating function of p olynomial in tegrals of motion K m and K ℓ of the m -th and m ± 1-th order in the momen ta , resp ectiv ely . As an example we ha v e K m = 2 ( p 1 u 1 P ′ 2 + p 2 u 2 P ′ 1 ) , κ 1 = 1 , κ 2 = 1 , K m = 2 P ′ 2  2 p 2 u 2 P ′ 1 + p 1 u 1 P ′ 2  + 8 p 1 u 1 p 2 2 u 2 2 f , κ 1 = 1 , κ 2 = 2 , K m = 2 P ′ 2 2  3 p 2 u 2 P ′ 1 + p 1 u 1 P ′ 2  + 8 p 2 2 u 2 2  p 2 u 2 P ′ 1 + 3 p 1 u 1 P ′ 2  f , κ 1 = 1 , κ 2 = 3 , (2.20) where m = 1 , 3, m = 3 , 5 m = 3 , 7, b ecause P ′ 1 , 2 and f are linear functions on H 1 , 2 , whic h are the second order p olynomials on momen ta. 7 The corresp onding expres sions for the K ℓ lo ok like K ℓ = P ′ 1 P ′ 2 + 4 p 1 p 2 u 1 u 2 f , κ 1 = 1 , κ 2 = 1 , K ℓ = P ′ 1 P ′ 2 2 + 4 f p 2 u 2 ( p 2 u 2 P ′ 1 + 2 p 1 u 1 P ′ 2 ) , κ 1 = 1 , κ 2 = 2 , K ℓ = P ′ 1 P ′ 2 3 + 12 P ′ 2 p 2 u 2 ( P ′ 2 p 1 u 1 + P ′ 1 p 2 u 2 ) f + 16 p 1 u 1 p 3 2 u 3 2 f 2 . κ 1 = 1 , κ 2 = 3 . (2.21) The imp o sed condition (2.17) leads to some restrictions on the functions v j ( q j ) and u j ( q j ). In fact, substituting canonical v a riables (2.4 ) into the equations (2.16) we obtain the follow ing express ion for the St¨ ac ke l matrix S =       αv 2 1 + α g 1 v 1 + α h 1 u 2 1 αv 2 2 + α g 2 v 2 + α h 2 u 2 2 β v 2 1 + β g 1 v 1 + β h 1 u 2 1 β v 2 2 + β g 2 v 2 + β h 2 u 2 2       , det S 6 = 0 . (2.22) So, f or a giv en κ 1 , 2 expressions for ϑ 2 j (2.18) yield tw o differen tial equations on functions u, v and parameters β : S 2 j ( q j ) = κ j v ′ j ( q j ) u j ( q j ) = ⇒ κ j u j v ′ j = β v j + β g j v j + β h j , j = 1 , 2 . (2.23) F or the St¨ ac k el systems with rational or tr ig onometric metrics, w e ha v e to solv e these equations in the space of the truncated Lauren t or F ourier p olynomials, respective ly . Prop osition 1 I f κ j 6 = 0 e quations (2.23) h ave the fol lowing thr e e monom ial solutions I β = 0 , β h j = 0 , u j = q j , v j = q β g j κ j j , I I β g j = 0 , β h j = 0 , u j = 1 , v j = − κ j ( β q j ) − 1 , I I I β = 0 , β g j = 0 , u j = 1 , v j = κ − 1 j β h j q j , (2.24) up to c an o n ic al tr ansf o rmations. The fourth solution ( IV) is the c ombination of the first and thir d solutions for the differ ent j ’s. In order to prov e this fact w e can substitute u = aq m and v = bq k in to the (2.23) and divide resulting equation on q m + k − 1 abk κ = b 2 β q k +1 − m + q 1 − m bβ g + q 1 − k − m β h . Finally , w e differen tiate it by q and mu ltiply on q m 0 = − ( m − k − 1) b 2 β q k − ( m − 1) bβ g − ( m + k − 1) β h q − k . Suc h a s b 6 = 0 and k 6 = 0 one gets three solutions (2.24) o nly . 8 Then w e suppose that after some p oin t transformation x = z 1 ( q ) , y = z 2 ( q ) , p x = w 11 ( q ) p 1 + w 12 ( q ) p 2 , p y = w 21 ( q ) p 1 + w 22 ( q ) p 2 , (2.25) where w ij 6 = 0, kinetic part of the Hamilton function H 1 = T + V has a sp ecial form T = X  S − 1  1 j p 2 j = g 11 ( x, y ) p 2 x + g 12 ( x, y ) p x p y + g 22 ( x, y ) p 2 y , where g is a metric on a configuratio na l manifold. F or instance, if w e supp ose tha t T = X  S − 1  1 j p 2 j = p x p y , then one gets the f o llo wing alg ebraic equations w 11 w 21 =  S − 1  11 , w 12 w 21 + w 11 w 22 = 0 , w 12 w 22 =  S − 1  12 (2.26) and the partia l differential equations { x, p x } = { y , p y } = 1 , { p x , y } = { p y , x } = { p x , p y } = 0 . (2.27) on parameters α and functions z 1 , 2 ( q 1 , q 2 ), w k j ( q 1 , q 2 ). The remaining free parameters γ , γ h j , γ g j determine the corr esp o nding p oten tial part of the Hamiltonia n V ( x, y ). In fact, since integrals H 1 , 2 is defined up to the trivial shifts H k → H k + c k , our p ot ential V ( x, y ) dep ends on three arbitra r y parameters only . Summing up, in order to get all the sup erintegrable systems on a complex Eu- clidean space E 2 ( C ) asso ciated with the addition theorem (2.8) w e hav e to solve equa- tions (2.23 ,2.26,2.27) with resp ect to functions u j ( q j ), v j ( q j ), z 1 , 2 ( q 1 , q 2 ), w k j ( q 1 , q 2 ) and parameters α and β . Example 3 Let us consider second solution from the list (2.24) at κ 1 = 1 and κ 2 = 2. In this case equations (2 .26,2.27) hav e the follow ing partial solution S =  1 0 1 q 2 1 4 q 2 2  , x = √ q 1 q 2 , p x = √ q 1 q 2 p 1 + 1 2 √ q 1 p 2 , y = √ q 1 q 2 , p y = √ q 1 q 2 p 1 − q 2 2 2 √ q 1 p 2 . Adding p otential t erms o ne gets tw o Riemann surfaces C 1 : µ 2 = H 2 λ 2 − H 1 λ − γ 1 , and C 2 : µ 2 = H 2 λ 2 − 2 γ 2 λ + 4 γ 3 where µ j = p j , λ j = q − 1 j . Solutions of the corres p onding separated v aria bles a r e the second order St¨ ak el integrals of motion, whic h in ph ysical v ariables lo ok lik e H 1 = p x p y + γ 1 xy + γ 2 p xy 3 + γ 3 y 2 , H 2 = ( p x x − p y y ) 2 4 − γ 2 r x y − γ 3 x y . (2.28) It is new in tegrable systems, whic h is missed in the kno wn lists of sup erin tegrable systems [1, 6, 7, 8]. 9 In this case in tegrals of motion K 5 (2.20) and K 6 (2.21) are the fifth and sixth order p olynomials in the momen ta, respective ly . Of course, w e can try to get quartic, cubic and quadratic integrals of mot ion K 4 , K 3 and K 2 from the recurrence r elat io ns K 5 = { K 4 , H 2 } , K 4 = { K 3 , H 2 } , K 3 = { K 2 , H 2 } (2.29) and the equation { H 1 , K j } = 0, j = 4 , 3 , 2. Solving first recurrence equation one gets quartic integral of motion K 4 = − 4( xp x − y p y ) 2 ( p 2 x + γ 1 y 2 ) − 4 γ 2 2 xy + 8 p x ( xp x − y p y ) γ 2 √ xy + 16 x ( p 2 x + γ 1 y 2 ) γ 3 y . The other recurrence relations ( 2.29) hav e not p olynomial solutions. Of course, w e can try mo dify recurrence relatio ns { K 3 , H 2 } = K 4 + F 4 ( H 1 , H 2 ) , { K 2 , H 2 } = K 3 + F 3 ( H 1 , H 2 ) in order to get cubic and quadratic inte gra ls of motio n. How ev er, using ansatz K 2 = h 1 ( x, y ) p 2 x + h 2 ( x, y ) p x p y + h 3 ( x, y ) p 2 y + h 4 ( x, y ) w e can directly prov e that there is not the additional quadra t ic in tegral of motion, whic h commute with H 1 (2.28). 3 The Drac h systems In 193 5 Jules Drac h published t wo articles on the Hamiltonian systems with the third order in tegra ls of mot io n on a complex Euclidean space E 2 ( C ) with the following Hamil- ton function [2] H 1 = p x p y + U ( x, y ) . (3.1) 10 Up to canonical transformations x → ax and y → by the corresp onding p o ten tials lo ok lik e [7, 1 2 ]: ( a ) U = α xy + β x r 1 y r 2 + γ x r 2 y r 1 , where r 2 j + 3 r j + 3 = 0 , ( b ) U = α √ xy + β ( y − x ) 2 + γ ( y + x ) √ xy ( y − x ) 2 , ( c ) U = α xy + β ( y − x ) 2 + γ ( y + x ) 2 , ( d ) U = α p y ( x − 1) + β p y ( x + 1) + γ x √ x 2 − 1 2 , ( e ) U = α √ xy + β √ x + γ √ y , ( f ) U = α xy + β y 2 x 2 + 1 √ x 2 + 1 + γ x √ x 2 + 1 , ( g ) U = α ( y + x ) 2 + β ( y − x ) + γ (3 y − x )( y − 3 x ) 3 , ( h ) U = ( y + mx 3 ) − 2 / 3  α + β ( y − mx/ 3) + γ ( y 2 − 14 mxy 3 + m 2 x 2 9 )  , ( k ) U = αy − 1 / 2 + β xy − 1 / 2 + γ x , ( l ) U = α  y − ρx 3  + β x − 1 / 2 + γ x − 1 / 2 ( y − ρx ) . Suc h as Drac h made some assumptions on the fo r m of the third order integrals of motion K 3 (3.6) in the calculation it is not immediately clear whether the o bta ined list is complete. 3.1 Non-separable systems. Let us discuss the Drac h systems, whic h can not b e reduced to the St¨ ac k el syste ms b y an y p oin t transformatio n of v ariables. The first system (a) is non-St¨ ac k el system related to the three-particle p erio dic T o da lattice in the cente r- of-mass frame [1 2] and there are global action-angle v ariables [3]. The (h) system is reduced to the St¨ ac k el system by non-p o int cano nical transforma- tion and, therefore, existenc e of the third order inte gra l of motion is related with this non-p oint transformation [12]. Later this system ha s b een redisco ve red by Holt [4]. F or the (k) case in the Drac h pap ers [2] w e can find Hamiltonian H ( k ) 1 = p x p y + αy − 3 / 2 + β xy − 3 / 2 + γ x (3.2) and the following cubic integral of motion K ( k ) 3 = 6 w ( x, y )  ∂ H ∂ x p y − p x ∂ H ∂ y  − P ( p x , p y , x, y ) , (3.3) 11 where P = 3 p 2 x p y , w = − y . It is easy to prov e that { H ( k ) 1 , K ( k ) 3 } 6 = 0 and, therefore, we ha ve to suggest the p ossibilit y of a small mistake in the Drac h pap ers [2]. F ollow ing to [12], if w e solv e equation { p x p y + U ( x, y ) , K ( k ) 3 } = 0 with res p ect to U ( x, y ), then one gets our case ( k) H 1 = p x p y + αy − 1 / 2 + β xy − 1 / 2 + γ x. On the other hand, w e hav e pr ov en directly that the Ha milto nian H ( k ) 1 (3.2) has one second order integral of motion H ( k ) 2 = p 2 x − 4 β y 1 / 2 + 2 γ y (3.4) and has not cubic integral of motion. Moreo v er, it is easy to see that quadratic in te- grals of motion H ( k ) 1 , 2 (3.2,3.4) can not b e reduced to the St¨ ac k el integrals b y a ny p oint transformation of v a riables. Belo w w e do not consider (a) and (h) systems and consider (k) case in our no t ation only . 3.2 Classification. F or the Dr a c h systems κ 1 = κ 2 = ± 1 , 1 / 2 a nd Φ 2 = exp(2 p f ω 2 ) =  P ′ 1 2 √ f + p 1 u 1   P ′ 2 2 √ f + p 2 u 2  = = 1 4 f  K ℓ + p f K m  (3.5) ma y b e considered as the generating function of the p olynomial in tegrals of motion (2.20-2.21) K m = 2  p 1 u 1 P ′ 2 + p 2 u 2 P ′ 1  , m = 1 , 3 , (3.6) K ℓ = P ′ 1 P ′ 2 + 4 p 1 p 2 u 1 u 2 f , ℓ = 2 , 4 , of the m -th and ℓ -th order, resp ectiv ely . It’s clear that m = 1 , 3 a nd ℓ = 2 , 4, b ecause P ′ 1 , 2 and f are linear functions on H 1 , 2 , which are second order p olynomials on momen ta. W e hav e to underline, tha t w e use differen t κ 1 = κ 2 2 = ± 1 , 1 / 2 for the agreemen t of K m (3.6) with the initial Drac h integrals o f mot ion [2] only . One gets thir d order p olynomial in tegral of motion K 3 (3.6) if and only if P ′ 1 ( λ ) or P ′ 2 ( λ ) dep ends on H 1 or H 2 . It leads to the additional restrictions on α ’s and β ’s 2 X k =1 ∂ 2 P j ( λ ) ∂ H k ∂ λ 6 = 0 for j = 1 or j = 2 . (3.7) In order to get all the superintegrable systems on a complex Euclidean space E 2 ( C ) asso ciated with addition theorem (2.8) w e hav e to solv e equations (2.2 3,2.26,2.27) and (3.7) at κ 1 , 2 = 1 with resp ect to the functions u j ( q j ), v j ( q j ), z 1 , 2 ( q 1 , q 2 ), w k j ( q 1 , q 2 ) and parameters α and β . 12 Prop osition 2 Th e D r ach lis t of the St¨ ackel systems with the cubic inte gr a l of motion (3.6) asso ciate d with the addition the or em (2.8) is c omplete up to c anonic al tr ansfo r- mations of the extende d phase sp ac e. The results of corr esp o nding calculations ma y b e jo ined in to the table: C 1 , 2 (2.16) subs. (2.4) z 1 , 2 (2.25) S b µ 2 = H 1 λ 2 + ( H 2 + 2 α ) λ − β + 2 γ µ 2 = H 1 λ 2 + ( H 2 − 2 α ) λ − β − 2 γ µ j = p j q j z 1 , 2 = ( q 1 ± q 2 ) 2 4  q 2 1 q 2 2 1 1  c µ 2 = α 4 λ 2 +  H 2 + H 1 2  λ + γ µ 2 = α 4 λ 2 +  H 2 − H 1 2  λ − β λ j = q 2 j κ j = 1 2 z 1 , 2 = q 1 ± q 2 2  1 2 − 1 2 1 1  d µ 2 = H 2 λ 2 − √ 8( α + β ) λ + H 1 − 2 γ µ 2 = H 2 λ 2 − √ 8( α − β ) λ + H 1 + 2 γ µ j = p j z 1 = q 2 1 + q 2 2 2 q 1 q 2 z 2 = q 1 q 2  1 1 1 q 2 1 1 q 2 2  f µ 2 = H 2 λ 2 −  γ 2 − H 1  λ − α 4 − β 2 µ 2 = H 2 λ 2 −  γ 2 + H 1  λ − α 4 + β 2 λ j = q − 1 j κ j = − 1 z 1 = q 1 − q 2 2 2 √ q 1 q 2 z 2 = √ q 1 q 2  1 q 1 − 1 q 2 1 q 2 1 1 q 2 2  e µ 2 = H 1 λ 2 + 2( β + γ ) λ + H 2 + 2 α µ 2 = H 1 λ 2 − 2( β − γ ) λ + H 2 − 2 α µ j = p j z 1 , 2 = ( q 1 ± q 2 ) 2 4  q 2 1 q 2 2 1 1  k µ 2 = γ 2 λ 2 + ( β + H 1 ) λ + H 2 + α µ 2 = γ 2 λ 2 + ( β − H 1 ) λ + H 2 − α λ j = q j κ j = 1 z 1 = q 1 − q 2 2 z 2 = ( q 1 + q 2 ) 2 4 ( q 1 − q 2 1 1 ) g µ 2 = − γ 3 λ 2 +  H 1 2 + H 2  λ + α µ 2 = − γ 3 λ 2 − β 4 λ + H 2 4 − H 1 8 µ 1 = p 1 q 1 , λ 1 = q 2 1 µ 2 =2 p 1 , λ 2 = q 2 κ j = 1 2 z 1 , 2 = q 1 ± q 2 2  1 2 − 1 2 1 1  Similar to the o scillator a nd the Kepler problem, the Kepler c hange o f the time t → e t , 13 where d e t = v ( q ) dt, v ( q ) = det S det e S , (3.8) relates the Drac h systems (b),(d) and (e) with t he sys tems (c),(f ) and (k), resp ectiv ely . Here S are the St¨ ac ke l matrices for (b),(d) and (e) systems and e S are the St¨ ac k el matrices for (c),(f ) and (k) systems . Remind, tha t these mat r ices S and e S hav e differen t first row only , see [11, 1 3]. 3.3 In tegrals of motion Using definitions (3.6) we can prov e that integral of motio n K 4 (3.6) is the function on H 1 , H 2 and K 3 K 2 4 = 16 h 1 h 2 f 2 + ( K 2 3 − 4 h 1 g 2 2 − 4 h 2 g 2 1 ) f + g 2 1 g 2 2 . (3.9) Substituting this expression into the defin ition of Φ 2 (3.5) we can get in tegral K 3 as function on the action-angle v ariables I 1 , 2 = H 1 , 2 and ω 2 . As usual, p olynomial algebra of integrals of motion H 1 , 2 and K 3 follo ws from the canonical brac ke ts (1.1) { H 1 , H 2 } = { H 1 , K 3 } = { H 1 , K 4 } = 0 , { H 2 , K 3 } = δ K 4 , { H 2 , K 4 } = δ f K 3 , (3.10) { K 3 , K 4 } = F Z ( H 1 , H 2 , K 3 ) , where • δ = 4, F I = 16 f ( g 1 h 2 + g 2 h 1 ) − 4 g 1 g 2 ( g 1 + g 2 ) for b,c cases; • δ = − 2, F I I = K 3 + 32 f h 1 h 2 − 4( g 2 1 h 2 + g 2 2 h 1 ) for d,f cases; • δ = 2, F I I I = 4 f ( g 2 1 + g 2 2 ) − 16 f 2 ( h 1 + h 2 ) for e,k cases; • δ = 4, F I V = 2 f ( g 2 1 + 8 g 1 h 2 ) − 8 f 2 h 1 − 4 g 1 g 2 2 for g case. The difference in the v alues of δ is related with the difference in κ ’s whic h has b een defined by the Drac h in tegrals of motion [2]. Of course, w e can put κ 1 = κ 2 = 1 in all the cases suc h that δ = 2 and p o lynomials F lo ok as in (4.1). It reduces p olynomials P 1 , 2 in the table only . As ab ov e (2.29), we can try to find a no t her second order p olynomial in tegral of motion K 2 from the equations K 3 = { H 2 , K 2 } , { H 1 , K 2 } = 0 . Solutions of these equations K 2 = ±  2 p 1 p 2 u 1 u 2 + 2 v 1 v 2 f + v 1 g 2 + v 2 g 1  = ± K 4 − g 1 g 2 2 f (3.11) 14 ha v e b een found in [7] in f ramew ork of the Lagrangian formalism. The a lgebras of quadratic in tegrals of motion H 1 , 2 and K 2 ha v e b een considered in [1]. There is some opinion that all sup erinte gra ble systems with quadratic (linear) in te- grals o f mo t ion a re multise para ble, i.e allow s the separation of v ariables in the Hamilton- Jacobi equation in at least t w o differen t co ordinate systems on the configuration space [6]. The some of the Drac h system s ma y b e considered as coun terexamples asso ciated with the Lie surfaces [1]. Namely , three of the superintegrable Dra c h systems with quadratic in tegrals H 1 , H 2 , K 2 are separable in the one co ordinate system on the configuration space only . Prop osition 3 F or the (b) and (c) D r ach systems inte gr als of motion H 1 , K 2 ar e sep- ar able in the c o or dinates x = q 2 2 q 1 , y = q 1 q 2 , and the c orr esp ondi n g sep ar ate d r elations do not al lows us to get cubic inte gr als of motion. F or the (e ) and (g) c ases inte gr als of m otion H 1 , K 2 ar e sep a r able in the c o or dinates x = q 1 − q 2 2 , y = − ( q 1 + q 2 ) 2 4 and we c a n use the c orr es p onding sep ar a te d r elations to the c onstruction of the cubic inte gr als of motion. F or the (d ), (f ) and (k) c ases quadr atic in te gr als o f motion H 1 and K 2 do n ot sep ar able by the p oint tr ansformations. W e can prov e this Prop osition by using computer program from [5]. 3.4 The (l) system. Without lost of g eneralit y we can put ρ = − 3 in the (l) case. Substituting this Hamil- tonian in to the computer program from [5] one gets the separated v ar ia bles x = ( q 1 − q 2 ) 2 2 , y = ( q 1 + q 2 ) 2 2 and the corresp onding separated relations p 2 j = P j ( q j ) = − 4 αq 4 j ∓ 8 √ 2 γ q 3 j + 4 H 1 q 2 1 ∓ 4 √ 2 β q j + H 2 , j = 1 , 2 . (3.12) whic h give rise to one h yp erelliptic curv e µ 2 = P ( λ ) at µ = p j and λ = ± q j . The angle v ariable ω 2 = 1 2 Z q 1 d λ p P ( λ ) + 1 2 Z q 2 d λ p P ( − λ ) = 1 2 Z q 1 d λ p P ( λ ) − 1 2 Z − q 2 d λ p P ( λ ) (3.13) 15 is a sum of the incomplete elliptic in tegrals of the first kind on the common hyperelliptic curv e. According to [15, 2] there is addition theorem and additional cubic in tegra l of motion K 3 = 2( e P ′ 1 p 2 + e P ′ 2 p 1 ) , whic h lo oks lik e a s the Drac h in tegral (3.6), but in this case functions e P ′ 1 , 2 = ( q 1 + q 2 ) 2 ∂ ∂ q 1 , 2 P ( ± q 1 , 2 ) ( q 1 + q 2 ) 4 ha v e completely another algebro-geometric explanation. All the details will be pub- lished in the f o rthcoming publications. As sequ ence, the alg ebra o f in tegrals of motion H 1 , 2 and K 3 differs from the corre- sp onding algebras for other Drac h system s relat ed with another additio n theorem. As an example, the recurrence c hain K j +1 = { H 2 , K j } terminates on the fo ur t hs step only K 7 = { H 2 , K 6 } = − 480 K 4 K 3 + 256 H 2 1 K 3 − 768 α H 2 K 3 − 3072 β γ K 3 . The solution of t he in v erse recurrence chain lo oks like K 2 = p 2 y + 2 α x − 4 γ √ x. It is in teresting, that the algebra of quadratic in tegrals o f motion H 1 , 2 and K 2 is one of the standard cubic algebras [1] and w e do not explanation of this fact. 4 New s up erin tegr abl e systems on z ero-ge nus h y- p erelliptic curv es at κ 1 = 1 and κ 2 = 2 , 3 Let us put κ 1 = 1 and κ 2 = 2 in (2.23) and try to solv e equations (2.26)-(2.27). Here is one sup erin tegra ble sy stem w ith cubic additional in tegral K m (2.20) and quadratic in tegral K ℓ (2.21) V I I I = γ 1 (3 x + y )( x + 3 y ) + γ 2 ( x + y ) + γ 3 ( x − y ) , S = ( a b 1 1 ) , and sev en systems with the real p o t en tials V I = γ 1 (3 x + y )( x + 3 y ) + γ 2 ( x + y ) 2 + γ 3 ( x − y ) 2 , S =  a/q 1 b/q 2 1 /q 1 2 /q 2  , V (1) I I = γ 1 xy + γ 2 p x 3 y + γ 3 x 2 , S =  1 /q 1 1 1 /q 2 1 4 /q 2 2  , V (2) I I = γ 1 √ xy + γ 2 x 2 + γ 3 y x 3 , S =  0 1 1 /q 2 1 4 /q 2 2  , V (3) I I = γ 1 √ xy + γ 2 p x 3 y + γ 3 x 5 / 4 y 3 / 4 , S =  1 0 1 /q 2 1 4 /q 2 2  , V (4) I I = γ 1 xy + γ 2 y x 3 + γ 3 y 3 x 5 , S =  0 4 /q 2 1 /q 2 1 4 /q 2 2  , V (1) I V = γ 1 √ xy + γ 2 ( √ x − √ y ) √ xy + γ 3 √ xy ( √ x + √ y ) 2 , S =  1 q 2 2 / 4 1 /q 1 1  , V (2) I V = γ 1 xy + γ 2 ( x − y ) + γ 3 ( x + y ) 2 , S =  a/q 1 b 1 /q 1 1  16 for whic h in tegra ls of motion K m and K ℓ (2.20-2.21) are fifth and sixth or der p olyno- mials in the momenta. Solution of the equations K m = ±{ H 2 , K m − 1 } and { H 1 , K m − 1 } = 0 lo oks lik e K m − 1 = 4 p 1 p 2 u 1 u 2 (2 f v 2 + g 2 ) + 4 v 2 (2 f v 1 + g 1 )( f v 2 + g 2 ) + (4 f h 2 + g 2 2 ) v 1 = 4 µ 2 ( µ 1 P ′ 2 + P ′ 1 ) − (4 f h 2 − g 2 2 ) λ 1 − 4 h 2 g 1 . It is additional in tegral of motion, whic h is second o r der p o lynomial for the system with p oten tial V I I I and fourth order po lynomial in the momen ta for the other sys tems. No w w e presen t some sup erin tegrable St¨ ac k el systems at κ 1 = 1 and κ 2 = 3. Here is one system with cubic additio na l in tegra l K m (2.20) V (1) I I I = γ 1 ( x + 2 y )(2 x + y ) + γ 2 ( x + 2 y ) + γ 3 (2 x + y ) , S = ( a b 1 1 ) , and sev en systems with the real p o t en tials V I = γ 1 ( x + 2 y )(2 x + y ) + γ 2 ( x + y ) 2 + γ 3 ( x − y ) 2 , S =  a/q 1 b/q 2 1 /q 1 3 /q 2  , V (1) I I = γ 1 xy + γ 2 x 2 / 3 y 4 / 3 + γ 3 x 1 / 3 y 5 / 3 , S =  1 /q 1 0 1 /q 2 1 9 /q 2 2  , V (2) I I = γ 1 √ xy + γ 2 √ y x 5 / 2 + γ 3 y 2 x 4 , S =  0 1 1 /q 2 1 9 /q 2 2  V (3) I I = γ 1 √ xy + γ 2 x 4 / 3 y 2 / 3 + γ 3 x 7 / 6 y 5 / 6 , S =  1 0 1 /q 2 1 9 /q 2 2  , V (4) I I = γ 1 xy + γ 2 y 2 x 4 + γ 3 y 5 x 7 , S =  0 1 /q 2 1 /q 2 1 9 /q 2 2  , V (2) I I I = γ 1 ( x 2 − 5 x √ y + 4 y ) + γ 2 x √ y + γ 3 √ y , S =  2 q 1 2 q 2 1 1  , V I V = γ 1 ( x + 5 y )(5 x + y ) + γ 2 ( x − y ) + γ 3 ( x − y ) 2 , S =  a/q 1 b 1 /q 1 1  for whic h in tegrals of motion K m and K ℓ (2.20-2.21) are sev en th and eigh ts order p olynomials in t he momen t a . The a lgebra of integrals of motion H 1 , 2 and K m (2.20) is the fifth or sev en th order p olynomial alg ebra in terms of t he co efficien t s of t he h yp erelliptic curv es { H 2 , K m } = 2 K ℓ , { H 2 , K ℓ } = 2 f K m , { K m , K ℓ } = ± F Z , where p olynomial F Z dep ends on the type o f solution (2.24) o nly: F I = 2(4 f h 2 − g 2 2 ) κ 2 − κ 1  4 f ( κ 2 1 h 2 g 1 + κ 2 2 h 1 g 2 ) − g 1 g 2 ( κ 2 2 g 1 + κ 2 1 g 2 )  , F I I = 4(4 f h 2 − g 2 2 ) κ 2 − κ 1  4 f ( κ 2 + κ 1 ) h 2 h 1 − κ 1 h 1 g 2 2 − κ 2 h 2 g 2 1  ∓ K 2 m , F I I I = 4(4 f h 2 − g 2 2 ) κ 2 − κ 1  4 f ( κ 1 h 2 + κ 2 h 1 ) − κ 1 g 2 2 − κ 2 g 2 1  f , (4.1) F I V = 2(4 f h 2 − g 2 2 ) κ 2 − κ 1  4 f (2 κ 2 f h 1 − κ 1 h 2 g 1 ) − 2 κ 2 f g 2 1 + κ 1 g 1 g 2 2  . Here c hoice o f sign + or − dep ends on κ ’s. 17 As ab ov e, the St¨ ac k el transformatio ns (3.8) relate systems asso ciated with one ty p e of the solutions (2.24), whereas algebra o f integrals of motion is inv ar ian t with resp ect to suc h tra nsformations. The complete classification of suc h sup erintegrable systems r equires further in v esti- gations. 5 Conclus ion W e discuss an application of the addition theorem to construction o f a lgebraic integrals of motion fro m the multi-v alued actio n- angle v ariables. W e prop ose new a lg orithm to construction of t he superintegrable St¨ ac k el sys tems asso ciated with ze ro- gen us h yp erelliptic curv es. It allows us to prov e that the Drach classification of the St¨ ac ke l sys tems with cubic in tegral of motion ( 3.6) a sso ciated with the addition theorem (2.8) is complete. Moreo v er, we presen t some new t wo-dimens ional sup erin tegrable system s with third, fifth and sev en th order integrals of mot io n. The prop osed metho d may b e a pplied t o construction of the higher order additional p olynomial integrals of motion fo r the n -dimensional sup erin tegrable St¨ ac ke l systems on the differen t manifolds. On the o ther hand, we prov e t ha t there are some sup erin- tegrable systems, whic h miss out of this construction. It will b e in teresting to study a mathematical mec hanism of the app earance such sup erin tegrable systems. The researc h w as partia lly supp ort ed b y the RF BR grant 06- 01-001 4 0. References [1] C. Da sk alo y annis, K . Ypsilan tis, Unifie d tr e atment and classific ation o f sup erinte- gr able systems with inte gr als quadr atic in momenta on a two-dim ensional manifo l d , J. Mat h. Ph ys., v.47, 2 0 06, 042904 , 38 pag es, math-ph/04120 5 5. [2] J. Drac h. Sur l’int ´ egr ation lo gique des ´ equations de la d ynamique ` a deux varia b les: F or c e s c onservatives. I n t ˆ egr ales cubiques. Mouvem ents dans le plan. Comptes Ren- dus, v.200, p.22- 26, 1 935. J. Drac h. Sur l’int´ egr ation lo gique et sur la tr ansformation des ´ equations de la dynamique ` a deux v a riables: F or c es c onservatives. Int´ egr ales cubiq ues , Comptes Rendus, v. 200, p.599- 602, 1935. [3] A. Henrici, T. Kapp eler, Glob al action-angle variables for the p erio d ic T o da l a ttic e , Preprin t: arXiv:0802.4032, 200 8. [4] C.R. Holt, Construction of new inte gr able Ham i l toni a ns in two d e gr e es of fr e e dom , J.Math.Ph ys., v.23, p.103 7 –1046, 1982. [5] Y u.A. Gr ig ory ev, A.V. Tsigano v, Symb olic softwar e for sep ar ation of variables in the Hamilton-Jac obi e quation for the L-systems , Regular and Chaotic Dynamics, v.10(4), p.413-42 2, 20 05. 18 [6] I. Marquette, P . Win t ernitz, Polynomial Poisson algebr as fo r classic a l sup erinte- gr able systems with a thir d-or der inte g r al of motion , J.Math.Phy s. v.48, p.01 2 902, 2007. Sup erinte gr able systems with a thir d or der in te gr als of m otion , Preprint: arXiv:0711.4783, 2007. [7] M.F.R a ˜ nada, Sup erinte gr ab le n = 2 systems, quadr atic c onstants of motion, and p otentials of Dr ach , J.Math.Ph ys., v.38, p.416 5 -4178, 1997. [8] M.F. Ranada, M. Santander, Complex Euclide an sup er-i n te gr able p otentials, p o- tentials o f D r ach, and p otential of Holt , Ph ys. Lett. A, v.278, p.27 1 –279, 2001. [9] P . St¨ ac kel, Ub er die Inte g r ation der Hamilton–Jac obische n Differ ential Gleich ung Mittelst S e p ar ation d er V ariab el , Habilitationssc hrift, Halle, 1891. [10] A.V. Tsigano v, The St¨ ackel systems and algebr aic curves , J. Math. Ph ys., v.40, p.279-298 , 1999. [11] A.V. Tsiganov, Duality b etwe en inte gr able St¨ ac kel systems , J. Ph ys.A: Math. Gen., v.32, p.7965–798 2 , 199 9. [12] A.V. Tsigano v, On the Dr ach sup eri n te gr able systems , J. Ph ys.A: Math. Gen., v.33, p.7407-742 3, 20 00. [13] A.V. Tsigano v, Th e Maup ertuis princi p le and c ano nic al tr ansform a tions of the extende d phase sp a c e , J. Nonlinear Math.Phy s, v.8(1), p.15 7-182, 2001. [14] A.V. Tsigano v, On maximal ly sup erinte gr able systems , Regular and Chaotic Dy- namics, v.13, p. 17 8 -190, 2008. [15] H. W eb er, El liptische F unktionen und algebr ais che Zahlen , View eg, Br a unsc h w eig, 1908. 19

Original Paper

Loading high-quality paper...

Comments & Academic Discussion

Loading comments...

Leave a Comment