  The inclusive jet cross-section has been measured in proton-proton collisions
at sqrt(s)=2.76 TeV in a dataset corresponding to an integrated luminosity of
0.20pb-1 collected with the ATLAS detector at the Large Hadron Collider in
2011. Jets are identified using the anti-kt algorithm with two radius
parameters of 0.4 and 0.6. The inclusive jet double-differential cross-section
is presented as a function of the jet transverse momentum pT and jet rapidity
y, covering a range of 20 <= pT < 430 GeV and |y| < 4.4. The ratio of the
cross-section to the inclusive jet cross-section measurement at sqrt(s)=7 TeV,
published by the ATLAS Collaboration, is calculated as a function of both
transverse momentum and the dimensionless quantity xT = 2 pT / sqrt(s), in bins
of jet rapidity. The systematic uncertainties on the ratios are significantly
reduced due to the cancellation of correlated uncertainties in the two
measurements. Results are compared to the prediction from next-to-leading order
perturbative QCD calculations corrected for non-perturbative effects, and
next-to-leading order Monte Carlo simulation. Furthermore, the ATLAS jet
cross-section measurements at sqrt(s)=2.76 TeV and sqrt(s)=7 TeV are analysed
within a framework of next-to-leading order perturbative QCD calculations to
determine parton distribution functions of the proton, taking into account the
correlations between the measurements.
