Publications by authors named "Evgeny A Stepanov"
Article Synopsis
- Understanding the physics of the single-orbital Hubbard model is crucial for grasping how metal-insulator transitions occur in real materials, particularly in the intermediate-coupling regime.
- Recent advanced techniques have helped analyze the spectral function in this intermediate regime, clarifying how antiferromagnetic fluctuations and local electronic correlations contribute to forming an insulating state.
- The study delineates the distinct Slater and Heisenberg regimes of the phase diagram, highlighting a crossover region where competing spatial and local electronic correlations affect the local magnetic moment and the overall insulating state.
Article Synopsis
- Spintronics and orbitronics can benefit from orbital-selective behaviors in correlated electron materials, particularly through phenomena like the orbital-selective Mott state.
- The study investigates the possibility of an orbital-selective Néel transition (OSNT), which involves different magnetic behaviors across orbitals and requires the absence of Hund's exchange coupling.
- Through two-orbital calculations, the research reveals that OSNT can occur across various interaction strengths, with different mechanisms (Slater or Heisenberg) governing the transition depending on the coupling regime.
Article Synopsis
- Diabetes increases the risk of ischemic stroke by worsening cerebral damage due to hyperglycemia, though the exact mechanisms are not fully understood.
- This study presents novel findings on the real-time dynamics of hydrogen peroxide (HO) in neuronal mitochondria during ischemic stroke, using advanced technology on both cultured cells and rat brains.
- Results indicate that high blood sugar doesn't impact HO generation in the ischemic area but does worsen the overall effects of the stroke, revealing how elevated glucose levels can alter mitochondrial function in neurons.
Article Synopsis
- - The text discusses
- orbital-selective electronic behavior
- , a unique feature of multiorbital systems where electrons can be localized in some orbitals while being itinerant in others, particularly highlighted by the phenomenon called the
- orbital-selective Mott transition (OSMT)
- - Current theoretical frameworks for understanding OSMT rely on local approaches like
- dynamical mean-field theory
- and
- slave spin methods
- , which do not fully account for broader spatial influences on electronic behavior.
- - The study explores the
- Hubbard-Kanamori model
- on a cubic lattice, revealing that strong
- magnetic fluctuations
- interfere with OSMT, resulting in a
- Néel transition
- occurring at the same
Article Synopsis
- - The study introduces a method for real-time monitoring of hydrogen peroxide and pH changes in rat stroke models using fiber-optic technology, allowing researchers to better understand the effects of ischemia on the brain.
- - By utilizing advanced fluorescent protein sensors and reconnectable fiber probes, the framework enables detailed, multi-site analysis of oxidative stress and acidosis during stroke events, which are critical markers of the condition.
- - The approach improves the accuracy of measurements by providing enhanced background noise reduction, making the results of in vivo stroke studies more reliable and statistically significant across different animal models.
Article Synopsis
- Characterizing nonlocal magnetic fluctuations in materials with strong electronic interactions is a big challenge in modern condensed matter theory, especially for perovskite materials.
- The authors developed a diagrammatic extension of dynamical mean-field theory and focused on a three-orbital model to explore how magnetic fluctuations behave under different conditions.
- They found that the nature of these fluctuations changes significantly with the strength of Hund's coupling, affecting how spins interact and leading to different orbital behaviors depending on electron filling.
Article Synopsis
- * The study uses advanced genetically encoded biosensors to observe intracellular pH and reactive oxygen species (ROS) dynamics during these processes in both cultured neurons and experimental stroke in rats.
- * Findings reveal a significant acidosis in the brain tissue almost immediately during the ischemic core, but notable ROS generation was only observed 24 hours later, indicating a disconnect between cell culture and actual metabolic processes in vivo.
Enhanced Error Decoding from Error-Related Potentials using Convolutional Neural Networks.
Annu Int Conf IEEE Eng Med Biol Soc
July 2018
Article Synopsis
- Error-related potentials play a crucial role in understanding human intentions during decision-making and interactions, whether with other humans or machines.
- The study presents a new approach that incorporates error-related potential activity into a two-dimensional feature set, using a Convolutional Neural Network to identify human errors in EEG data.
- Using the BNCI2020 - Monitoring Error-Related Potential dataset, the proposed method achieved an impressive error detection accuracy of 79.8%, surpassing existing techniques.