The discovery of the most compact detached white dwarf (WD) binary SDSS
J065133.33+284423.3 has been discussed in terms of probing the tidal effects in
white dwarfs. This system is also a verification source for the space-based
gravitational wave (GW) detector, evolved Laser Interferometer Space Antenna
(eLISA) which will observe short-period compact Galactic binaries with
Porbββ²5 hrs. We address the prospects of doing tidal studies using
eLISA binaries by showing the fractional uncertainties in the orbital decay
rate and the rate of that decay, fΛβ,fΒ¨β expected from both the GW
and EM data for some of the high-f binaries. We find that fΛβ and
fΒ¨β can be measured using GW data only for the most massive WD binaries
observed at high-frequencies. Form timing the eclipses for βΌ10 years, we
find that fΛβ can be known to βΌ0.1 for J0651. We find that from
GW data alone, measuring the effects of tides in binaries is (almost)
impossible. We also investigate the improvement in the knowledge of the binary
parameters by combining GW amplitude and inclination with EM data with and
without fΛβ. In our previous work we found that EM data on distance
constrained 2-Ο uncertainty in chirp mass to 15β25 whereas adding
fΛβ reduces it to 0.11. EM data on fΛβ also constrains
2-Ο uncertainty in distance to 35. EM data on primary mass
constrains the secondary mass m2β to factors of 2 to βΌ40 whereas adding
fΛβ reduces this to 25. And finally using single-line spectroscopic
constrains 2-Ο uncertainties in both the m2β,d to factors of 2 to
βΌ40. Adding EM data on fΛβ reduces these 2-Ο uncertainties
to β€25 and 6 respectively. Thus we find that EM measurements of
fΛβ and radial velocity will be valuable in constraining binary
parameters.Comment: 10 pages, 3 figures, Accepted for publication in Ap