# Publications in Physics

## Journals

### 1999

** J. Esparza, J.L. Lopez and J. Sesma: **
Zeros of the Whittaker function associated to Coulomb Waves

IMA Journal of Applied Mathematics 63(1), 1999, pp. 71--88.

### 1991

** A. Cruz and J. Esparza and J. Sesma: **
Zeros of the Hankel function of real order out of the principal
Riemann sheet

Journal of Computational and Applied Mathematics 37, 1991, pp. 89-99.

**Keywords:** Hankel function, zeros.

**Abstract:**
*
Zeros of the Hankel function of real order follow, as the order varies
continuously, trajectories across different Riemann sheets
of the complex plane. A discussion of the main features of these
trajectories is presented.
*