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Topic Review
Scorpius
Scorpius, known as "the Scorpion," is a striking constellation visible in the southern celestial hemisphere during the summer months. With its distinctive shape resembling a scorpion's curved tail, Scorpius is one of the most recognizable constellations in the night sky. 
  • 518
  • 15 Mar 2024
Biography
Reimar Lüst
Reimar Lüst (German: [ˈʁaɪmaʁ ˈlyːst]; 25 March 1923 – 31 March 2020)[1] was a German astrophysicist. He worked in European space science from its beginning, as the scientific director of the European Space Research Organisation (ESRO) from 1962 and as Director General of the European Space Agency (ESA) from 1984 until 1990. Lüst taught internationally and influenced German politics a
  • 518
  • 29 Dec 2022
Biography
Nima Arkani-Hamed
Nima Arkani-Hamed (Persian: نیما ارکانی حامد‎; born April 5, 1972) is an Iranian-American-Canadian[1][2] theoretical physicist, with interests in high-energy physics, quantum field theory, string theory, cosmology and collider physics. Arkani-Hamed is a member of the permanent faculty at the Institute for Advanced Study in Princeton, New Jersey.[3] He is also director of The Cent
  • 517
  • 01 Dec 2022
Topic Review
Free Entropy
A thermodynamic free entropy is an entropic thermodynamic potential analogous to the free energy. Also known as a Massieu, Planck, or Massieu–Planck potentials (or functions), or (rarely) free information. In statistical mechanics, free entropies frequently appear as the logarithm of a partition function. The Onsager reciprocal relations in particular, are developed in terms of entropic potentials. In mathematics, free entropy means something quite different: it is a generalization of entropy defined in the subject of free probability. A free entropy is generated by a Legendre transformation of the entropy. The different potentials correspond to different constraints to which the system may be subjected.
  • 517
  • 04 Nov 2022
Topic Review
Lieb-Robinson Bounds
The Lieb-Robinson bound is a theoretical upper limit on the speed at which information can propagate in non-relativistic quantum systems. It demonstrates that information cannot travel instantaneously in quantum theory, even when the relativity limits of the speed of light are ignored. The existence of such a finite speed was discovered mathematically by Elliott H. Lieb and Derek W. Robinson (de) in 1972. It turns the locality properties of physical systems into the existence of, and upper bound for this speed. The bound is now known as the Lieb-Robinson bound and the speed is known as the Lieb-Robinson velocity. This velocity is always finite but not universal, depending on the details of the system under consideration. For finite-range, e.g. nearest-neighbor, interactions, this velocity is a constant independent of the distance travelled. In long-range interacting systems, this velocity remains finite, but it can increase with the distance travelled. In the study of quantum systems such as quantum optics, quantum information theory, atomic physics, and condensed matter physics, it is important to know that there is a finite speed with which information can propagate. The theory of relativity shows that no information, or anything else for that matter, can travel faster than the speed of light. When non-relativistic mechanics is considered, however, (Newton's equations of motion or Schrödinger's equation of quantum mechanics) it had been thought that there is then no limitation to the speed of propagation of information. This is not so for certain kinds of quantum systems of atoms arranged in a lattice, often called quantum spin systems. This is important conceptually and practically, because it means that, for short periods of time, distant parts of a system act independently. One of the practical applications of Lieb-Robinson bounds is quantum computing. Current proposals to construct quantum computers built out of atomic-like units mostly rely on the existence of this finite speed of propagation to protect against too rapid dispersal of information. 
  • 517
  • 20 Oct 2022
Topic Review
Ursa Major
Ursa Major, often referred to as the Great Bear, is one of the most recognizable and prominent constellations in the northern celestial hemisphere. Its distinctive shape, resembling a large bear with a long tail, has captivated human imagination for millennia. At the heart of Ursa Major lies the Big Dipper, a prominent asterism formed by seven bright stars that serve as a navigational guide and cultural icon across cultures and civilizations.
  • 517
  • 15 Mar 2024
Topic Review
Simulation Argument (Coding Planck Units)
Coding Planck units for deep universe (Programmer God) Simulation Hypothesis models The deep universe simulation hypothesis or simulation argument is the argument that the universe in its entirety, down to the smallest detail, could be an artificial simulation, such as a computer simulation. A deep universe simulation begins with the big bang and is programmed by an external intelligence (external to the universe), this intelligence by definition a Programmer God in the creator of the universe context. In Big Bang cosmology, the Planck epoch or Planck era is the earliest stage of the Big Bang, where cosmic time was equal to Planck time. Thus for a deep universe simulation, Planck time can be used as the reference for the simulation clock-rate, with the simulation operating at or below the Planck scale, and with the Planck units as (top-level) candidates for the base (mass, length, time, charge) units.
  • 515
  • 22 Nov 2022
Topic Review
Testing General Relativity with Gravitational Waves
The detections of gravitational-wave (GW) signals from compact binary coalescence by ground-based detectors have opened up the era of GW astronomy. These observations provide opportunities to test Einstein’s general theory of relativity at the strong-field regime. 
  • 515
  • 18 Jan 2022
Topic Review
Polymer Waveguide-Based Sensors
The optical waveguide (WG) is one of the fundamental components of integrated photonics. Polymer WGs can operate in either single-mode (with core diameters between 2 μm and 5 μm) or multimode (with core dimensions generally between 30 μm and 500 μm) regimes. They are both entirely consistent with the matching optical fiber type due to the similar mode field diameter. A WG is simply utilized as a light link to connect external instruments to a sampling point or an optical sensing element in an extrinsic sensor. In biomedicine, environmental monitoring, process control, and safety, extrinsic sensors are already widely employed.
  • 514
  • 08 Mar 2023
Topic Review
Jet Flavour Tagging
Jet Flavour Tagging briefly describes the main algorithms used to reconstruct heavy-flavour jets. Jet Substructure and Deep Tagging focuses on the identification of heavy-particle decay in boosted jets. These so-called tagger algorithms have a relevant role in physics studies since they allow researchers to successfully reconstruct and identify the particles that caused the jet and, in some cases, allow analyses that would otherwise be unfeasible.
  • 512
  • 09 Nov 2022
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