Phys.org November 19, 2024 Researchers in the Republic of Korea investigated Coulomb exchange between distinct electron–hole modes and Floquet states, in two-dimensional semiconductors through a theoretical description of time-resolved and angle-resolved photoemission spectroscopy (tr-ARPES) in an extended Haldane model that included the electron–hole Coulomb interaction. Two branches of novel quantum states were found in the form of bosonic exciton–Floquet composites, which resulted from exchange coupling due to the Coulomb interaction. tr-ARPES could be directly employed for the density matrix element of the biparticle subsystem of photoelectron and hole, and electron–hole entanglement and information could be further explored. According to the […]
Tag Archives: Entanglement
Pseudomagic quantum states: A path to quantum supremacy
Phys.org June 11, 2024 An international team of researchers (USA – Harvard University, MIT, University of Chicago, Germany) introduced “pseudomagic” ensembles of quantum states that are computationally indistinguishable from those with high nonstabilizerness. They demonstrated that pseudomagic neither follows from pseudoentanglement nor implies it. It offers fresh insights into the theory of quantum scrambling: it uncovers states that, even though they originated from nonscrambling unitaries, remain indistinguishable from scrambled states to any physical observer. Applications include new lower bounds on state synthesis problems, property testing protocols, and implications for quantum cryptography. According to the researchers only quantities measurable by a […]
‘Ghostly’ Glow of Entangled Light Now Reveals Hidden Objects Better Than Ever
Science Alert February 24, 2023 Ghost imaging involves the exploitation of non-local photon spatial correlations to image objects with light that has not interacted with them and, using intelligent spatial scanning with projective masks, reduces detection to a single pixel. Despite many applications, extension to complex amplitude objects remains challenging. Researchers in South Africa revealed that the necessary interference for phase retrieval was naturally embedded in the correlation measurements formed from traditional projective masks in bi-photon quantum ghost imaging. Using this, they developed a simple approach to obtain the full phase and amplitude information of complex objects. They demonstrated straightforward […]
New measurements quantifying qudits provide glimpse of quantum future
Science Daily October 13, 2022 An international team of researchers (USA – Oak Ridge National Laboratory, Purdue University, industry, Switzerland) combined state-of-the-art frequency-bin production with state-of-the-art light sources to develop an effective technique to characterize high-dimensional qudit entanglement. They fully characterized an entangled pair of eight-level qudits, which formed a 64-dimensional quantum space — quadrupling the previous record for discrete frequency modes. The researchers began their experiments by shining a laser into a micro-ring resonator — a circular, on-chip device fabricated and designed to generate nonclassical light. This powerful photon source which took 1 square millimeter of space and allowed […]
A sound idea: a step towards quantum computing
Science Daily June 19, 2019 An international team of researchers (Japan, USA – University of Pittsburgh) used very short laser pulses to excite electrons inside a silicon crystal creating coherent vibrations of the silicon structure, such that the motions of the electron and the silicon atoms became entangled. The state of the system was then probed after a variable delay time with a second laser pulse. Based on their theoretical model, the scientists were able to explain oscillations observed in the charge generated as a function of delay time. The research may lead to quantum computers based on existing silicon […]