Identical Particles Of Mass Research Articles

Unbounded Energy Collisions inside and outside Black Holes

The possibility of on-horizon collisions of unbounded energy in the case of an extreme Kerr black hole is known as the BSW effect. It is also a widely accepted point of view that the energy collision of two identical particles of mass m near the horizon of a Schwarzschild black hole is limited to a value of 25 m. We show that there are two possible scenarios for unbounded energy collisions both for the exterior and for the interior of spherically symmetric black holes. Similar scenarios are found for axially symmetric black holes. It is shown that divergent (infinite) energy on-(inner)horizon collisions are excluded due to the anisotropic character of the dynamics of black hole interiors.

On the asymptotic behavior in the scattering problem for several charged quantum particles interacting via repulsive pair potentials

The ansatz proposed earlier by Buslaev and Levin [Funct. Anal. Appl. 46, 147 (2012)] for describing the leading order in the asymptotic behavior of continuum eigenfunctions in the scattering problem for three charged quantum particles is extended to the system of n charged quantum particles of identical mass and identical charge. It is shown that the proposed ansatz generates a fast decreasing (faster than the potential) discrepancy of the Schrodinger equation for a set of asymptotic configurations.

Macroscopic quantum tunneling of two coupled particles in the presence of a transverse magnetic field

Two coupled particles of identical mass but opposite charge are studied, with a constant transverse external magnetic field and an external potential, interacting with a bath of harmonic oscillators. We show that the problem cannot be mapped to a one-dimensional problem like the one in Ao (Phys. Rev. Lett. 72, 1898 (1994)), it strictly remains two-dimensional. We calculate the effective action both for the case of linear coupling to the bath and without a linear coupling using imaginary time path integral at finite temperature. At zero temperature we use Leggett’s prescription to derive the effective action. In the limit of zero magnetic field we recover a two-dimensional version of the result derived in Chudnovsky (Phys. Rev. B, 54, 5777 (1996)) for the case of two identical particles. We find that in the limit of strong dissipation, the effective action reduces to a two-dimensional version of the Caldeira–Leggett form in terms of the reduced mass and the magnetic field. The case of ohmic dissipation with the motion of the two particles damped by the ohmic frictional constant η is studied in detail.

Bound states and scattering lengths of three two-component particles with zero-range interactions under one-dimensional confinement

The universal three-body dynamics in ultracold binary gases confined to one-dimensional motion is studied. The three-body binding energies and the (2 + 1)-scattering lengths are calculated for two identical particles of mass m and a different particle of mass m 1, whose interaction is described in the low-energy limit by zero-range potentials. The critical values of the mass ratio m/m 1 at which three-body states occur and the (2 + 1)-scattering length vanishes are determined for both zero and infinite interaction strength λ1 of the identical particles. A number of exact results are listed and asymptotic dependences for both m/m 1 → ∞ and λ1 → −∞ are derived. Combining the numerical and analytic results, we deduce a schematic diagram showing the number of three-body bound states and the sign of the (2 + 1)-scattering length in the plane of the mass ratio and the interaction-strength ratio. The results provide a description of the homogeneous and mixed phases of atoms and molecules in dilute binary quantum gases.

Universal three-body dynamics in binary mixtures of ultra-cold atoms

The universal three-body dynamics in ultra-cold binary Fermi and Fermi-Bose mixtures is studied. A comprehensive universal description of the rotational-vibrational spectrum for two identical particles of mass m and the third particle of mass m 1 in the zero-range limit of the interaction between different particles is given for arbitrary values of the mass ratio m/m 1 and the total angular momentum L. For those L and m/m 1, which correspond to the finite number of vibrational states, all the binding energies are described by the universal function depending on two scaled variables. The detailed study is performed for L = 1; in particular, it is shown that a two-hump structure in the mass-ratio dependencies of the elastic scattering cross section and the three-body recombination rate are connected with arising of the bound states.

Universal description of the rotational-vibrational spectrum of three particles with zero-range interactions

A comprehensive universal description of the rotational-vibrational spectrum for two identical particles of mass m and a third particle of mass m 1 in the zero-range limit of the interaction between different particles is given for arbitrary values of the mass ratio m/m 1 and the total angular momentum L. It is found that the number of vibrational states is determined by the functions L c(m/m 1) and L b(m/m 1). Explicitly, if the two-body scattering length is positive, the number of states is finite for L c(m/m 1) ≤ L ≤ L b(m/m 1), zero for L > L b(m/m 1), and infinite for L < L c(m/m 1). If the two-body scattering length is negative, the number of states is zero for L ≥ L c(m/m 1) and infinite for L < L c(m/m 1). For the finite number of vibrational states, all the binding energies are described by the universal function ɛLN(m/m 1) = (ξ, η), where ξ = (N − 1/2)/√L(L + 1), η = √m/[m 1 L(L + 1)], and N is the vibrational quantum number. This scaling dependence is in agreement with the numerical calculations for L > 2 and only slightly deviates from those for L = 1, 2. The universal description implies that the critical values L c(m/m 1) and L b(m/m 1) increase as 0.401 √m/m 1 and 0.563 √m/m 1, respectively, while the number of vibrational states for L ≥ L c(m/m 1) is within the range N ≤ N max ≈ 1.1√L(L + 1) + 1/2.

Statistics of Mass Aggregation in a Self-Gravitating One-Dimensional Gas

We study at the microscopic level the dynamics of a one-dimensional, gravitationally interacting sticky gas. Initially, N identical particles of mass m with uncorrelated, randomly distributed velocities fill homogeneously a finite region of space. It is proved that at a characteristic time a single macroscopic mass is formed with certainty, surrounded by a dust of nonextensive fragments. In the continuum limit this corresponds to a single shock creating a singular mass density. The statistics of the remaining fragments obeys the Poisson law at all times following the shock. Numerical simulations indicate that up to the moment of macroscopic aggregation the system remains internally homogeneous. At the short time scale a rapid decrease in the kinetic energy is observed, accompanied by the formation of a number \( \sim \sqrt N \) of aggregates with masses \( \sim m\sqrt N \).