Stellar binary black holes in the LISA band: a new class of standard
  sirens
  The recent Advanced LIGO detections of coalescing black hole binaries (BHBs)
imply a large population of such systems emitting at milli-Hz frequencies,
accessible to the Laser Interferometer Space Antenna (LISA). We show that these
systems provide a new class of cosmological standard sirens. Direct LISA
luminosity distance -$D_l$- measurements, combined with the inhomogeneous
redshift -$z$- distribution of possible host galaxies provide an effective way
to populate the $D_l-z$ diagram at $z<0.1$, thus allowing a precise local
measurement of the Hubble expansion rate. To be effective, the method requires
a sufficiently precise LISA distance determination and sky localization of a
sizeable number of BHBs, which is best achieved for a 6-link detector
configuration. We find that, for a BHB population consistent with current
fiducial LIGO rates, the Hubble constant $H_0$ can be determined at the
$\sim$5% and $\sim$2% level (68% confidence) assuming two and five million Km
arm-length respectively.
