%0 Journal Article %T Statistical mechanics of coupled supercooled liquids in finite dimensions %+ Laboratoire Charles Coulomb (L2C) %+ Laboratoire de Physique Théorique de la Matière Condensée (LPTMC) %A Guiselin, Benjamin %A Berthier, Ludovic %A Tarjus, Gilles %< avec comité de lecture %@ 2542-4653 %J SciPost Physics %I SciPost Foundation %V 12 %N 3 %P 091 %8 2022 %D 2022 %Z 2105.08946 %R 10.21468/SciPostPhys.12.3.091 %Z Physics [physics]/Physics [physics]/General Physics [physics.gen-ph]Journal articles %X We study the statistical mechanics of supercooled liquids when the system evolves at a temperature $T$ with a field $\epsilon$ linearly coupled to its overlap with a reference configuration of the same liquid sampled at a temperature $T_0$. We use mean-field theory to fully characterize the influence of the reference temperature $T_0$, and we mainly study the case of a fixed, low-$T_0$ value in computer simulations. We numerically investigate the extended phase diagram in the $(\epsilon,T)$ plane of model glass-forming liquids in spatial dimensions $d=2$ and $d=3$, relying on umbrella sampling and reweighting techniques. For both $2d$ and $3d$ cases, a similar phenomenology with nontrivial thermodynamic fluctuations of the overlap is observed at low temperatures, but a detailed finite-size analysis reveals qualitatively distinct behaviors. We establish the existence of a first-order transition line for nonzero $\epsilon$ ending in a critical point in the universality class of the random-field Ising model (RFIM) in $d=3$. In $d=2$ instead, no phase transition is found in large enough systems at least down to temperatures below the extrapolated calorimetric glass transition temperature $T_g$. Our results confirm that glass-forming liquid samples of limited size display the thermodynamic fluctuations expected for finite systems undergoing a random first-order transition. They also support the relevance of the physics of the RFIM for supercooled liquids, which may then explain the qualitative difference between $2d$ and $3d$ glass-formers. %G English %2 https://hal.science/hal-03245252/document %2 https://hal.science/hal-03245252/file/SciPostPhys_12_3_091.pdf %L hal-03245252 %U https://hal.science/hal-03245252 %~ CNRS %~ L2C %~ LPTMC %~ UNIV-MONTPELLIER %~ SORBONNE-UNIVERSITE %~ SORBONNE-UNIV %~ SU-SCIENCES %~ SU-TI %~ ALLIANCE-SU %~ UM-2015-2021 %~ UM-EPE