Search

For the classical N-body problem in R d with d ≧ 2 , Maderna–Venturelli in their remarkable paper (Ann Math 192:499–550, 2020) proved the existence of hyperbolic motions with any positive energy constant, starting from any configuration and along any non-collision configuration. Their original proof relies on the long time behavior of solutions by Chazy 1922 and Marchal-Saari 1976, on the Hölder estimate for Mañé’s potential by Maderna 2012, and on the weak KAM theory. We give a new and completely different proof for the above existence of hyperbolic motions. The central idea is that, via some geometric observation, we build up uniform estimates for Euclidean length and angle of geodesics of Mañé’s potential starting from a given configuration and ending at the ray along a given non-collision configuration. Moreover, our geometric approach works for Hamiltonians 1 2 ‖ p ‖ 2 - F (x) , where F (x) ≧ 0 is lower semicontinuous and decreases very slowly to 0 faraway from collisions. We therefore obtain the existence of hyperbolic motions to such Hamiltonians with any positive energy constant, starting from any admissible configuration and along any non-collision configuration. Consequently, for several important potentials F ∈ C 2 (Ω) , we get similar existence of hyperbolic motions to the generalized N-body system x ¨ = ∇ x F (x) , which is an extension of Maderna–Venturelli [Ann Math 2020]. [ABSTRACT FROM AUTHOR]

It is shown that each lobe of the figure-eight orbit is star-shaped, which indicates that the corresponding polar angle is monotone. In general, it is not clear under which assumptions a trajectory in a minimizer is star-shaped. In this paper, we study minimizers connecting two fixed-ends (i.e. the Bolza problem) in the planar three-body problem with two equal masses. We show that if the Jacobi coordinates of the two fixed-ends are both orthogonal, then for any minimizer, both Jacobi vectors describe a star-shaped curve. If the Jacobi coordinates are orthogonal only on one of the fixed-ends and they are in adjacent closed quadrants, then their polar angles have at most one critical point. As an application, we show the existence and prove some geometric properties of two families of periodic orbits. [ABSTRACT FROM AUTHOR]

It has been shown by Chen that if all masses are in the same proper vector subspace of R d (d ≥ 2) on one of the free boundaries, local minimizers connecting the two free boundaries have no collision on that boundary. However, not much is known for other types of boundary configurations. In this paper, we consider minimizers connecting two free boundaries and study possible quadruple collisions under the following four symmetric configurations: isosceles trapezoid configuration, rectangular configuration, double isosceles configuration and diamond configuration. Whenever the boundary configuration of four bodies coincides with one of the four symmetric configurations, we show that these four bodies are free of quadruple collision on that boundary set. New ideas and detailed analysis are introduced in order to construct deformed paths in some of the cases and estimate their action values. As its applications, we show the existence of several sets of periodic orbits in the planar four-body and five-body problems. [ABSTRACT FROM AUTHOR]

It is shown that in the planar equal-mass four-body problem, there exist two sets of action minimizers connecting two planar boundary configurations with fixed symmetry axes and specific order constraints: a double isosceles configuration and an isosceles trapezoid configuration, while order constraints are introduced on the boundary configurations. By applying the level estimate method, these minimizers are shown to be collision-free and they can be extended to two new sets of periodic or quasi-periodic orbits. [ABSTRACT FROM AUTHOR]

We study the linear stability of a two-parameter family of periodic orbits in the parallelogram four-body problem. This family was numerically found and named as double–double orbits by Vanderbei. A demonstration of such an orbit is shown. By introducing new transformations and applying Roberts' symmetry reduction method, the linear stability can be simplified to the calculation of two eigenvalues. A global picture of linear stability of this set with respect to the two parameters is given for the first time. Actually, most of the double–double orbits are numerically proved to be linearly stable. [ABSTRACT FROM AUTHOR]

This work studies periodic orbits as action minimizers in the spatial isosceles three-body problem with mass . In each period, the body with mass moves up and down on a vertical line, while the other two bodies have the same mass , and rotate about this vertical line symmetrically. For given , such periodic orbits form a one-parameter set with a rotation angle as the parameter.Two new phenomena are found for this set. First, for each , this set of periodic orbits bifurcate from a circular Euler (central configuration) orbit to a Broucke (collision) orbit as increases from to . There exists a critical rotation angle , where the orbit is a circular Euler orbit if ; a spatial orbit if ; and a Broucke (collision) orbit if . The exact formula of is numerically proved to be . Second, oscillating behaviors occur at rotation angle for all . Actually, the orbit with runs on its initial periodic shape for only a few periods. It breaks the first periodic shape and becomes irregular in a moment. However, it runs close to a different periodic shape after a while. In a short time, it falls apart from the second periodic shape and runs irregularly again. Such oscillation continues as time increases. Up to , the orbit is bounded and keeps oscillating between periodic shapes and irregular motions. Further study implies that, for each , the angle between any two consecutive periodic shapes is a constant. When , similar oscillating behaviors are expected. [ABSTRACT FROM AUTHOR]

In the three-body problem, it is known that there exists a special set of periodic orbits: spatial isosceles periodic orbits. In each period, one body moves up and down along a straight line, and the other two bodies rotate around this line. In this work, we revisit this set of orbits by applying variational method. Two unexpected phenomena are discovered. First, this set is not always spatial. It actually bifurcates from the circular Euler (central configuration) orbit to the Broucke (collision) orbit. Second, one of the orbits in this set encounters an oscillating behavior. By running its initial condition, the orbit stays periodic for only a few periods before it becomes irregular. However, it moves close to another periodic shape in a while. Shortly it falls apart again and starts running close to a third periodic shape after a moment. This oscillation continues as t increases. Actually, up to t = 1.2 × 105, the orbit is bounded and keeps oscillating between periodic shapes and irregular motions. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we study the existence and linear stability of the Broucke periodic orbit in the planar three-body problem. In each period of this orbit, there are two binary collisions (or BC for short) between the outer bodies, while the inner body reaches its minimum or maximum at the time of each BC. A surprising simple existence proof of this orbit is given. The initial condition of this orbit is shown to be a supremum of some well-chosen set. The linear stability is then analyzed by Robertsʼ symmetry reduction method. It is shown that the Broucke periodic orbit with equal masses is linearly stable. [Copyright &y& Elsevier]

Abstract: In this paper, we study the existence and linear stability of the rhomboidal periodic orbit in the planar equal mass four-body problem. The Hamiltonian of the differential system is regularized by a Levi–Civita type transformation and an appropriate scaling of time. The initial condition of this orbit is shown to be the infimum of some well-chosen set. This existence proof is direct and surprisingly simple. Further, a careful study shows that this orbit has a symmetry group isomorphic to the dihedral group . Then Robertsʼ symmetry reduction method is applied to show the linear stability. It turns out that the rhomboidal periodic orbit in the planar equal mass four-body problem is linearly stable. [Copyright &y& Elsevier]

This paper gives an analytic existence proof of the Schubart periodic orbit with arbitrary masses, a periodic orbit with singularities in the collinear three-body problem. A 'turning point' technique is introduced to exclude the possibility of extra collisions and the existence of this orbit follows by a continuity argument on differential equations generated by the regularized Hamiltonian. [ABSTRACT FROM AUTHOR]

This paper gives an analytic proof of the existence of Schubart-like orbit, a periodic orbit with singularities in the symmetric collinear four-body problem. In each period of the Schubart-like orbit, there is a binary collision (BC) between the inner two bodies and a simultaneous binary collision (SBC) of the two clusters on both sides of the origin. The system is regularized and the existence is proved by using a 'turning point' technique and a continuity argument on differential equations of the regularized Hamiltonian. [ABSTRACT FROM AUTHOR]

For each given n ≥ 2 , we study the variational existence of a new spatial periodic orbit in the 2n-body problem. Besides excluding possible collision singularities, the main challenges left are to show that the orbit is not a relative equilibrium and it is spatial. By introducing a new estimate in the collinear central configuration, we can prove that it is not a relative equilibrium in the 2n-body problem. Furthermore, with the help of numerical calculation, the orbit is spatial in the equal-mass four-body problem. [ABSTRACT FROM AUTHOR]

We analytically prove the existence of a symmetric periodic simultaneous binary collision orbit in a regularized planar pairwise symmetric equal mass four-body problem. This is an extension of our previous proof of the analytic existence of a symmetric periodic simultaneous binary collision orbit in a regularized planar fully symmetric equal mass four-body problem. We then use a continuation method to numerically find symmetric periodic simultaneous binary collision orbits in a regularized planar pairwise symmetric 1, m, 1, m four-body problem for m between 0 and 1. Numerical estimates of the the characteristic multipliers show that these periodic orbits are linearly stability when 0.54 ≤ m ≤ 1, and are linearly unstable when 0 < m ≤ 0.53. [ABSTRACT FROM AUTHOR]

A correction to the article "Existence and Stability of Symmetric Periodic Simultaneous Binary Collision Orbits in the Planar Pairwise Symmetric Four-Body Problem" that was published in the March 31, 2012 online issue is presented.