Second dome of superconductivity in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>YBa</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>Cu</mml:mi><mml:mn>3</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>7</mml:mn></mml:msub></mml:mrow></mml:math> at high pressure

Evidence is growing that a second dome of high-${T}_{\mathrm{c}}$ superconductivity can be accessed in the cuprates by increasing the doping beyond the first dome. Here, we use ab initio methods without invoking any free parameters, such as the Hubbard $U$, to reveal that pressure could turn ${\mathrm{YBa}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{7}$ into an ideal candidate for second dome superconductivity, displaying the predicted signature of strongly hybridized ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ and ${d}_{{z}^{2}}$ orbitals. Notably, pressure is found to induce a phase transition replacing the antiferromagnetic phases with an orbitally degenerate $d\ensuremath{-}d$ phase. Our study suggests that the origin of the second dome is correlated with the oxygen-hole fraction in the ${\mathrm{CuO}}_{2}$ planes and the collapse of the pseudogap phase.