MECII-originating type 2 dentate spikes (DSM) promote dominance of CA1 slow (∼40-Hz) over mid-frequency (∼80-Hz) gamma oscillations when CA1 represents non-local recollections. Dvorak et al. show that DSM coordinates cofiring within DG, CA3, and CA1 networks and optimizes discharge timing between DG and CA1 for information transfer during memory recall.
The Breit-Wheeler process which produces matter and antimatter from photon collisions is experimentally investigated through the observation of 6085 exclusive electron-positron pairs in ultraperipheral Au+Au collisions at √sNN=200 GeV. The measurements reveal a large fourth-order angular modulation of cos4Δϕ=(16.8±2.5)% and smooth invariant mass distribution absent of vector mesons (ϕ, ω, and ρ) at the experimental limit of ≤0.2% of the observed yields. The differential cross section as a function of e+e− pair transverse momentum P⊥ peaks at low value with √⟨P2⊥⟩=38.1±0.9 MeV and displays a significant centrality dependence. These features are consistent with QED calculations for the collision of linearly polarized photons quantized from the extremely strong electromagnetic fields generated by the highly charged Au nuclei at ultrarelativistic speed. The experimental results have implications for vacuum birefringence and for mapping the magnetic field which is important for emergent QCD phenomena.
Researchers from Skoltech, KTH Royal Institute of Technology, and Uppsala University have predicted the existence of antichiral ferromagnetism, a nontrivial property of some magnetic crystals that opens the door to a variety of new magnetic phenomena. The paper was published in the journal Physical Review B.
Chirality, or handedness, is an extremely important fundamental property of objects in many fields of physics, mathematics, chemistry and biology; a chiral object cannot be superimposed on its mirror image in any way. The simplest chiral objects are human hands, hence the term itself. The opposite of chiral is achiral: a circle or a square are simple achiral objects.
Chirality can be applied to much more complex entities; for instance, competing internal interactions in a magnetic system can lead to the appearance of periodic magnetic textures in the structure that differ from their mirror images—this is called chiral ferromagnetic ordering. Chiral crystals are widely considered promising candidates for magnetic data storage and processing device realization as information can be encoded via their nontrivial magnetic textures.
Partition functions are ubiquitous in physics: They are important in determining the thermodynamic properties of many-body systems and in understanding their phase transitions. As shown by Lee and Yang, analytically continuing the partition function to the complex plane allows us to obtain its zeros and thus the entire function. Moreover, the scaling and nature of these zeros can elucidate phase transitions. Here, we show how to find partition function zeros on noisy intermediate-scale trapped-ion quantum computers in a scalable manner, using the XXZ spin chain model as a prototype, and observe their transition from XY-like behavior to Ising-like behavior as a function of the anisotropy. While quantum computers cannot yet scale to the thermodynamic limit, our work provides a pathway to do so as hardware improves, allowing the future calculation of critical phenomena for systems beyond classical computing limits.
Interacting quantum systems exhibit complex phenomena including phase transitions to various ordered phases. The universal nature of critical phenomena reduces their description to determining only the transition temperature and the critical exponents. However, numerically calculating these quantities for systems in new universality classes is complicated because of critical slowing down, requiring increasing resources near the critical point. An alternative approach is to analytically continue the calculation of the partition function to the complex plane and determine its zeros.
The partition function is a positive function of multiple real parameters representing physical quantities such as temperature and applied fields. When the partition function is analytically continued in one of the respective parameters, its zeros show notable structure for a variety of models of interest. Lee and Yang (1, 2) studied the partition function zeros of Ising-like systems in the complex plane of the magnetic field h and found that, at the critical temperature (and in the thermodynamic limit), the loci of zeros pinch to the real axis. Alternatively, Fisher (3) studied the partition function zeros by making the inverse temperature β complex.
MIT researchers suggest a way to protect qubit states using a phenomenon called many-body localization (MBL) — a peculiar phase of matter that is unlike solid or liquid, and never reaches equilibrium.
Resistive-switching memory (RSM) is an emerging candidate for next-generation memory and computing devices, such as storage-class memory devices, multilevel memories and as a synapse in neuromorphic computing. A significant challenge in the global research efforts towards better energy technologies is efficient and accurate device modeling. Now, researchers have created a new modeling toolkit which can predict the current of a new type of memory with excellent accuracy.
Intel’s new approach to chips, details.
The new Alder Lake chips, however, are aspiring to be far more ambitious. Intel teased a full range of chips from 9W to 125W that would utilize the new hybrid approach, combining multiple high-end performance cores with efficient cores for a wider range of power when users need it and efficiency when running less strenuous tasks.
Given that Intel’s announcements today largely focused on the architectures, there are no hard product announcements, but the company did tease several planned Alder Lake SoCs that would utilize the new cores. Those include a desktop SoC with eight performance cores, eight efficiency cores, and integrated memory, graphics, and I/O; a laptop SoC with six performance cores, eight efficiency cores, imaging, Thunderbolt 4 support, memory, I/O, and more powerful Xe graphics all integrated in; and an ultramobile-focused SoC with two performance cores and eight efficiency cores.
Samsung Pay can now store your coronavirus vaccination card on your smartphone in the U.S., thanks to the CommonHealth app on the Play Store.
After Google added support for COVID-19 vaccination cards to Google Pay, Samsung has now announced that it is doing the same with Samsung Pay. Users of the service will be able to load their SMART Health Cards displaying their COVID-19 vaccination status within Samsung Pay. This will allow U.S. consumers to download a verifiable digital version of their vaccination record from pharmacies or health systems and securely store in on their smartphone via the CommonHealth app on supported Samsung Galaxy smartphones.
The unusual feature, measuring 3,000 light-years long, could represent a previously unknown type of galactic substructure.
The 23rd SpaceX
Commonly known as SpaceX, Space Exploration Technologies Corp. is a private American aerospace manufacturer and space transportation services company that was founded by Elon Musk in 2002. Headquartered in Hawthorne, California, the company designs, manufactures, and launches advanced rockets and spacecraft.
