Violations of Bell’s Inequality for Macroscopic States
Einstein referred to the nonlocal collapse of the wave function as “spooky action at adistance”. John Bell later showed that the hidden-variable theories advocated by Einstein wereinconsistent with the predictions of quantum mechanics. This distinction between quantum andclassical behavior is not limited to microscopic particles, and Bell’s inequality can be violated bymacroscopic systems as well. We recently showed that a photon number state incident on abeam splitter will produce two output states whose phases are entangled [1]. We also showed
ETH, EE, OTOC, & QFI
In his second week of residence at the University of Maryland, College Park, Prof. Srednicki will expand his portrait of thermalization of many-body quantum systems by introducing and explaining the eigenstate thermalization hypothesis, entanglement entropy, out-of-time-order correlations and quantum Fisher information.
Synthetic lattices for synthetic quantum matter
In recent decades, artificial quantum "materials" built from ultracold atoms, ultracold molecules, and light have enabled the exploration of a range of phenomena of relevance to condensed matter physics, as well as the realization of entirely new states of matter with no direct analogs.
Superconductivity wins election over dissipation
In 1962 Josephson predicted that an electric current can flow with no applied voltage through a thin insulating layer separating two superconductors. Since then, such "Josephson junction" has become has become the routinely used in many quantum electronic circuits (squids magnetometers, parametric amplifiers, superconducting qubits,...) and its use in the Volt metrology has helped reshape the International System of Units around quantum effects.
Coherence and decoherence in the Harper-Hofstadter model
Understanding how and when closed quantum systems lose or retain coherence is a central intellectual and practical question in quantum science. In rare cases, such as collisional narrowing or environment assisted tunneling, random processes can enhance coherence processes. In this talk, I will present a new addition to this list—the quasi-periodic lattice described by the Harper-Hofstadter (HH) model in a highly-elongated tube geometry, by showing that the dynamics can be immune to environmental noise.
Ultracold bubbles in space: atomic physics aboard the International Space Station
Exploring the effects of geometry, topology, dimensionality, and interactions on ultracold atomic ensembles has proven to be a continually fruitful line of inquiry. One heretofore unexplored configuration for such ensembles is that of a bubble or shell, where trapped atoms are confined in the vicinity of a spherical or ellipsoidal surface.
Harnessing biosystems for quantum information science
It is well known that architectures for quantum sensing and quantum information processing require exceptional isolation from sources of decoherence, including electromagnetic and thermal noise, by shielding and cooling. Could robust room-temperature alternatives be envisioned using biosystems that are optimized for certain quantum processes in warm, wet, and wiggly environments?
Quantum In The Wild
RSVP: go.umd.edu/dulny
The importance of the spectral gap in estimating ground-state energies
The field of quantum Hamiltonian complexity lies at the intersection of quantum many-body physics and computational complexity theory, with deep implications to both fields. The main object of study is the LocalHamiltonian problem, which is concerned with estimating the ground-state energy of a local Hamiltonian. A major challenge in the field is to understand the complexity of the LocalHamiltonian problem in more physically natural parameter regimes.