  We present high time-resolution ULTRACAM optical and NOTCam infrared
observations of the edge-on black hole X-ray transient Swift J1357.2-0933. Our
data taken in 2012 and 2013 show the system to be at its pre-outburst magnitude
and so the system is in quiescence. In contrast to other X-ray transients, the
quiescent light curves of Swift J1357.2-0933 do not show the secondary star's
ellipsoidal modulation. The optical light curve is dominated by variability
with an optical fractional rms of ~35 per cent, a factor of >3 larger than what
is observed in other systems at similar time-resolution. Optical flare events
lasting 2-10min with amplitudes of up to ~1.5 mag are seen as well as numerous
rapid ~0.8 mag dip events which are similar to the optical dips seen in
outburst. Similarly the infrared J-band light curve is dominated by variability
with a fractional rms of ~21 per cent and flare events lasting 10--30 min with
amplitudes of up to ~1.5 mag are observed. The quiescent optical to
mid-infrared spectral energy distribution in quiescence is dominated by a
non-thermal component with a power--law index of -1.4, (the broad-band rms SED
has a similar index) which arises from optically thin synchrotron emission most
likely originating in a weak jet; the lack of a peak in the spectral energy
distribution rules out advection-dominated models. Using the outburst
amplitude--period relation for X-ray transients we estimate the quiescent
magnitude of the secondary star to lie in the range V_min=22.7 to 25.6, which
when combined with the absolute magnitude of the expected M4.5 V secondary star
allows us to constrain to the distance to lie in the range 0.5 to 6.3 kpc.
(Abridged)
