We use bosonization methods to calculate the exact finite-temperature
single-electron Green's function of a spinful Luttinger liquid confined by open
boundaries. The corresponding local spectral density is constructed and
analyzed in detail. The interplay between boundary, finite-size and thermal
effects are shown to dramatically influence the low-energy properties of the
system. In particular, the well-known zero-temperature critical behavior in the
bulk always crosses over to a boundary dominated regime in the vicinity of the
Fermi level. Thermal fluctuations cause an enhanced depletion of spectral
weight for small energies E, with the spectral density scaling as E^2 for E
much less than the temperature. Consequences for photoemission experiments are
discussed.Comment: 18 pages in revtex format including 5 embedded figures (using epsf).
The latest complete postscript file is available from
http://fy.chalmers.se/~eggert/papers/longlutt.ps or by request from
[email protected]. To appear in Phys. Rev. B (Dec. 1997