Direct determination of the strange and light quark condensates from full lattice QCD

Understand

We determine the strange quark condensate from lattice QCD for the first time and compare its value to that of the light quark and chiral condensates.

• The results come from a direct calculation of the expectation value of the trace of the quark propagator followed by subtraction of the appropriate perturbative contribution, derived here, to convert the non-normal-ordered $m\bar{\psi}\psi$ to the $\bar{MS}$ scheme at a fixed scale.
• This is then a well-defined physical `nonperturbative' condensate that can be used in the Operator Product Expansion of current-current correlators.
• The perturbative subtraction is calculated through $\mathcal{O}(\alpha_s)$ and estimates of higher order terms are included through fitting results at multiple lattice spacing values.