Elementary particle physics rests on the discovery of particles produced in high-energy collider experiments. Now, a model collision above the threshold for particle production has been simulated on a quantum computer.
Maxwell’s demon may produce work using the information it obtains by measuring the system as fuel. Now, it is shown that the amount of produced work increases if the demon takes information about the dynamical correlations of the system into account.
When repulsion overcomes their tendency to move freely, electrons can arrange into a crystal. Two experiments have now identified Wigner polarons, quasiparticles whose optical signatures reveal the collective response of the electron lattice.
High-temperature cuprate superconductors remain a key platform for studying the competition and coexistence of emergent quantum phases of matter. These include non-s-wave superconductivity with a high transition temperature, non-Fermi-liquid transport and the pseudogap regime. How superconductivity emerges alongside and competes with the pseudogap remains an open question. Here, by directly accessing the near-antinodal region of optimally doped Bi-based cuprates via time- and angle-resolved photoemission, we report a transient change from a symmetric superconducting-like density of states to an asymmetric pseudogap-like density of states when superconductivity is disrupted by a sufficiently high excitation fluence. We observe this change at electronic temperatures well below the equilibrium superconducting critical temperature. Conversely, when superconductivity is fully restored, the pseudogap is suppressed, as indicated by a particle–hole-symmetric density of states. We also observe the coexistence of pseudogap and superconducting features at intermediate times or intermediate fluence. Our findings challenge the view that superconductivity emerges from phase coherence in the pseudogap. Instead, we show that the two states compete and that the low-temperature ground state of cuprates reflects an interplay between the superconducting and pseudogap states. How superconductivity relates to the pseudogap in cuprates remains unclear. Now, time-resolved photoemission measurements show a light-induced pseudogap-like state below critical temperature, revealing a dynamic interplay with superconductivity.
