DENSITY-MATRIX RENORMALIZATION-GROUP STUDY OF ONE-DIMENSIONAL ACOUSTIC PHONONS

We study the application of the density-matrix renormalization group t o systems with one-dimensional acoustic phonons. We show how the use o f a local oscillator basis circumvents the difficulties with the long- range interactions generated in real space using the normal phonon bas is. When applied to a harmonic atomic chain, we find excellent agreeme nt with the exact solution even when using a modest number of oscillat or and block states (a few times ten). We discuss the use of this algo rithm in more complex cases and point out its value when other techniq ues are deficient.