Researchers have made a breakthrough in THz frequency conversion using graphene.
Graphene is an allotrope of carbon in the form of a single layer of atoms in a two-dimensional hexagonal lattice in which one atom forms each vertex. It is the basic structural element of other allotropes of carbon, including graphite, charcoal, carbon nanotubes, and fullerenes. In proportion to its thickness, it is about 100 times stronger than the strongest steel.
The ultimate multi-messenger astronomy event would have gravitational waves, particles, and light arriving all at once. Did that just occur?
Posted in materials, particle physics | Leave a Comment on A New Meta: Realizing Negative Refraction of Light Using Atomic Media A novel platform towards applications such as powerful lenses and cloaking devices
Using laser trapped atom lattices instead of solid metamaterials to achieve negative refraction!
A Beam of Light Undergoing Negative Refraction Within a Lattice of Laser-Trapped Atoms.
Highlights:
In the grand sweep of scientific history, revolutions in thought are often born from a simple yet unsettling realization: that the fundamental nature of reality is not what we once assumed it to be. In the 20th century, physics was shaken by the twin cataclysms of relativity and quantum mechanics, revealing that space and time themselves were malleable, that particles could exist in superpositions, and that observation played a fundamental role in shaping what we call reality.
Light-sensitive nanoparticles promise a wide range of applications, for example in the field of sensor technology or energy generation. However, these require knowledge and control of the processes taking place within them. Plasmons, collective electron movements in the nanoparticle which transport energy, are essential in the behaviour of such nanoparticles.
Time-resolved experiments in the attosecond range reveal now that the importance of electronic correlations in these plasmons increases when the size of a system decreases to scales of less than one nanometre.
The study, published in the journal Science Advances (“Correlation-driven attosecond photoemission delay in the plasmonic excitation of C 60 fullerene”), was led by the University of Hamburg and DESY as part of a collaboration with Stanford, SLAC National Accelerator Laboratory, Ludwig-Maximilians-Universität München (LMU), Northwest Missouri State University, Politecnico di Milano and the Max Planck Institute for the Structure and Dynamics of Matter (MPSD).
A team of physicists at Fudan University, working with colleagues from Henan University, both in China, and from Nanyang Technological University, in Singapore and Donostia International Physics Center, in Spain, has developed a way to generate topological structures in surface water using gravity water waves. In their study published in Nature, the group used their technique to generate structures such as wave vortices, skyrmions and Möbius strips.
Prior research has shown that various types of waves can be used to achieve desired goals in a variety of applications; optical tweezers, for example, are used to capture and manipulate individual or groups of molecules to create materials or test molecular properties. Sound waves can be used to control much larger particles, or even objects, such as the membrane in a stereo speaker.
For this new study, the research team found a way to generate topological structures on the surface of water by taking advantage of the noise that develops when waves are laid on top of one another, giving them topological properties that can be used to generate wave fields.
When we divide matter into its fundamental, indivisible components, are those particles truly point-like, or is there a finite minimum size?
A very high-energy muon observed by the KM3NeT experiment in the Mediterranean Sea is evidence for the interaction of an exceptionally high-energy neutrino of cosmic origin.
The appearance of the Interstellar Objects (ISOs) Oumuamua and Comet Borisov in 2017 and 2019, respectively, created a surge of interest.
What were they? Where did they come from? Unfortunately, they didn’t stick around and wouldn’t cooperate with our efforts to study them in detail. Regardless, they showed us something: Milky Way objects are moving around the galaxy.
We don’t know where either ISO came from, but there must be more – far more. How many other objects from our stellar neighbours could be visiting our Solar System?
