Much of the focus of modern condensed matter physics concerns control of quantum phases with examples that include flat band superconductivity in graphene bilayers (1), the interplay of magnetism and ferroelectricity (2), and induction of topological transitions by strain (3). Here we report the first observation of a reproducible and strong enhancement of the superconducting critical temperature, Tc, in strontium titanate (SrTiO3) obtained through careful strain engineering of interacting superconducting phase and the polar quantum phase (quantum paraelectric). Our results show a nearly 50% increase in Tc with indications that the increase could become several hundred percent. We have thus discovered a means to control the interaction of two quantum phases through application of strain, which may be important for quantum information science. Further, our work elucidates the enigmatic pseudogap-like and preformed electron pairs phenomena in low dimensional strontium titanate (4, 5) as potentially resulting from the local strain of jammed tetragonal domains. Main text:Among the main goals of this work is to address the open question of the nature of the superconducting pairing mechanism in strontium titanate (STO) (6, 7) and to inspire searches for enhanced superconducting temperatures in materials not just with suppressed to zero Kelvin structural transitions, as in (CaxSr1−x)3Rh4Sn13 (8), MoTe2 (9) and Lu(Pt1−xPdx)2In ( 10), but with incipient quantum phase transitions, for example, ScF3 which has a structural quantum phase transition (11), and may become superconducting when doped (12). It has been predicted that superconducting doped strontium titanate with its peculiar phonon dynamics (13-17) is an example of a superconductivity arising near an incipient quantum polar (quantum ferroelectric) phase transition (4,7,(18)(19)(20)(21)(22)(23)(24)(25)(26)(27), but this has not been fully demonstrated experimentally, in part, due to the fact that existing results on isotope effect and Ca substitution (25, 28) may be explained by non-uniformity in the chemical composition, and the absolute enhancement of the critical temperature values have not been found.It is also unusual to find a pseudogap-like behavior in superconductors that cannot be explained by compositional inhomogeneities, as is the case in cuprates (29). A pseudogap-like behaviors, such as a tunneling gap and a 2e charge transport, occur in STO at temperatures up to about 0.9 K, almost twice the bulk superconducting transition temperature (4, 5).

Cryogenic quantum sensing techniques are developing alongside the ever-increasing requirements for noiseless experimental environments. For instance, several groups have isolated internal system vibrations from cold heads in closed-cycle dilution refrigerators. However, these solutions often do not account for external vibrations, necessitating novel strategies to isolate the entire cryogenic systems from their environments in a particular set of raised cryostats. Here, we introduce a dual-stage external active vibration-isolation solution in conjunction with a closed-cycle dilution refrigerator that isolates it from the environment. This dual stage includes two sets of active attenuators and a customized steel tower for supporting experimental probes at heights of 3 m from the floor. Both stages achieve 20-40 dB of attenuation with the active systems engaged, corresponding to levels of vibration in the VC-G range (a standardized Vibration Criterion appropriate for extremely quiet research spaces) on the cryostat's room temperature baseplate and the steel tower. Our unique vibration isolation solution therefore expands the applications of modern cryogenic equipment beyond exclusively quiet specialty buildings, rendering such equipment suitable for interdisciplinary, open-floor research centers.