Bad metal and strange metal behavior of normal-state of cuprates: an emergent Bose liquid perspective*

High-temperature non-saturating resistivity (so-called “bad metal” behavior), and low-temperature T-linear resistivity (so-called “strange metal” behavior) are well-known puzzles that signifies the non-Fermi liquid nature of the normal-state of cuprates. Here we investigate the temperature-dependent dynamical conductivity of an emergent Bose liquid and found that it reproduces most key features of the observed optical conductivity of cuprates, including the puzzling featureless continuum and the mid-infrared peak. Amazingly, the corresponding resistivity demonstrates both bad metal and strange metal behavior, with simple physical explanations. The results even display similar doping dependence to the experimental data. Our results not only support the notion that the low-energy physics of cuprates are dominant by an emergent Bose liquid, but also suggest a new paradigm to the non-Fermi liquid transport properties of a class of strongly correlated materials.