Showing posts with label topology. Show all posts
Showing posts with label topology. Show all posts

Monday, May 15, 2023

Origami Moments


Researchers detail never-before-seen properties in a family of superconducting Kagome metals
Feb 2023, phys.org

Superconductors that can operate at close to room temperature are considered the holy grail of condensed-matter physics because of the tremendous technological opportunities they would open in power efficiency, including in electricity transmission, transportation and quantum computing.

The new study focuses on superconductor RbV3Sb5, which is made of the metals rubidium vanadium and antimony. The material earns its namesake because of its peculiar atomic structure, which resembles a basketweave pattern that features interconnected star-shaped triangles. Kagome materials fascinate researchers because of the insight they provide into quantum phenomena, bridging two of the most fundamental fields of physics—topological quantum physics and condensed matter physics.

They showed that the structure moves from a 2x2x1 pattern with a signature Star of David pattern to a 2x2x2 pattern. This happens because the Kagome lattice inverts in on itself when the temperature gets extremely frigid. The new lattice it transitions into is made up largely of separate hexagons and triangles, the researchers showed. They also showed how this pattern connects when they take one plane of the RbV3Sb5 structure and rotate it, ''gazing '' into it from a different angle. [Sounds like magical kagome nano sandwiches to me.]

via Brown University: Jonathan Frassineti et al, Microscopic nature of the charge-density wave in the kagome superconductor RbV3Sb5, Physical Review Research (2023). DOI: 10.1103/PhysRevResearch.5.L012017


Origami-inspired robots can sense, analyze and act in challenging environments
Apr 2023, phys.org

Origami about to have its moment:

By embedding flexible and electrically conductive materials into a pre-cut, thin polyester film sheet, the researchers created a system of information-processing units, or transistors, that can be integrated with sensors and actuators. They then programmed the sheet with simple computer analogical functions that emulate those of semiconductors. Once cut, folded and assembled, the sheet transformed into an autonomous robot that can sense, analyze and act in response to their environments with precision. The researchers named their robots "OrigaMechs," short for Origami MechanoBots.

via UCLA Wenzhong Yan et al, Origami-based integration of robots that sense, decide, and respond, Nature Communications (2023). DOI: 10.1038/s41467-023-37158-9


Monday, May 1, 2023

The Photonic Phreakout


Optical this and photon that, opto-genetics, opto-electronics, opto-dildonics. Optical quantum computers made of crystals and light, the fastest computers you can imagine, tuned lasers that can bleep your brain through your retina and treat depression, and optical tractor beams, that's right, aka quantum tweezers.

This is not to detract from the renewed interest in the fundamental nature of time, by way of "time crystals", and of something I will call time lasers, because where there's crystals there's lasers, but that idea hasn't been discovered yet. 


Laser attack blinds autonomous vehicles, deleting pedestrians and confusing cars
Oct 2022, phys.org

Expertly timed lasers shined at an approaching lidar system can create a blind spot in front of the vehicle large enough to completely hide moving pedestrians and other obstacles

via University of Florida, the University of Michigan and the University of Electro-Communications in Japan: Yulong Cao et al, You Can't See Me: Physical Removal Attacks on LiDAR-based Autonomous Vehicles Driving Frameworks, arXiv (2022). DOI: 10.48550/arxiv.2210.09482.

 
Researchers create an optical tractor beam that pulls macroscopic objects
Jan 2023, phys.org

Optical manipulation such as levitation and rotation: Optical tweezers, for example, are commonly used scientific instruments that use laser light to hold and manipulate tiny objects such as atoms or cells. We could also use laser light to create an optical tractor beam.

via QingDao University of Science and Technology in China: Lei Wang et al, Macroscopic laser pulling based on the Knudsen force in rarefied gas, Optics Express (2022). DOI: 10.1364/OE.480019


Deep learning-designed diffractive processor computes hundreds of transformations in parallel
Jan 2023, phys.org

Optical computers use light instead of electricity to perform computations, and now they can make massively parallel, wavelength-multiplexed diffractive processors.

via SPIE International Society for Optics and Photonics and UCLA: Jingxi Li et al, Massively parallel universal linear transformations using a wavelength-multiplexed diffractive optical network, Advanced Photonics (2023). DOI: 10.1117/1.AP.5.1.016003

AI Art - Cymatics - 2022

A new type of photonic time crystal gives light a boost
Apr 2023, phys.org

While some physicists were initially skeptical that time crystals could exist, recent experiments have succeeding in creating them.

"We found that reducing the dimensionality from a 3D to a 2D structure made the implementation significantly easier, ..."

via Aalto University, Karlsruhe Institute of Technology, and Stanford University: Xuchen Wang et al, Metasurface-Based Realization of Photonic Time Crystals, Science Advances (2023). DOI: 10.1126/sciadv.adg7541.


Optical switching at record speeds opens door for ultrafast, light-based electronics and computers
Mar 2023, phys.org

Imagine a home computer operating 1 million times faster than the most expensive hardware on the market. Light-based optical computing with optical transistors is a marked improvement from the semiconductor-based transistors that currently run the world.

Data transfer speeds exceeding a petahertz, measured at the attosecond time scale.

via University of Arizona: Dandan Hui et al, Ultrafast optical switching and data encoding on synthesized light fields, Science Advances (2023). DOI: 10.1126/sciadv.adf1015


Recreating the double-slit experiment that proved the wave nature of light in time, instead of space
Apr 2023, phys.org

Now, a team led by Imperial College London physicists has performed the experiment using "slits" in time rather than space. They achieved this by firing light through a material that changes its properties in femtoseconds (quadrillionths of a second), only allowing light to pass through at specific times in quick succession.

The team next want to explore the phenomenon in a "time crystal," which is analogous to an atomic crystal, but where the optical properties vary in time.

Co-author Professor Stefan Maier said, "The concept of time crystals has the potential to lead to ultrafast, parallelized optical switches."

via Imperial College London: Romain Tirole et al, Double-slit time diffraction at optical frequencies, Nature Physics (2023). DOI: 10.1038/s41567-023-01993-w. 

Light shaped into a twisted smoke ring - Y Shen and Z Zhu at SPIE King's College - 2023

Post Script:
Topology also plays a big part in the coming light hype cycle -- you might know topology as Gödel, Escher, Bach's Eternal Golden Braid, but it also has a strong link to the hyperbolic geometries of hallucinogenic hero doses. They make quantum computers work better, so we're trying to tie light into knots to make mega-sentient intelligentities, faster.

Photonic hopfions: Light shaped as a smoke ring that behaves like a particle
Jan 2023, phys.org

Topology, hyperbolic geometry, toroids, skyrmions, and now -- new, very unusual, structured-light family of 3D topological solitons, the photonic hopfions, where the topological textures and topological numbers can be freely and independently tuned. 

via SPIE International Society for Optics and Photonics, University of Southampton, and King's College London: Yijie Shen et al, Topological transformation and free-space transport of photonic hopfions, Advanced Photonics (2023). DOI: 10.1117/1.AP.5.1.015001


Friday, September 9, 2022

Quantum Update


Quantum physics in proteins - AI affords unprecedented insights into how biomolecules work
Nov 2021, phys.org

I hear the quantum biology headlines humming.

via Deutsches Elektronen-Synchrotron: Abbas Ourmazd, Few-fs resolution of a photoactive protein traversing a conical intersection, Nature (2021). DOI: 10.1038/s41586-021-04050-9



Physicists create compressible optical quantum gas
Mar 2022, phys.org

Calling BECs (Bose-Einstein Condensate) a "super photon" by the way.

via University of Bonn: Erik Busley et al, Compressibility and the equation of state of an optical quantum gas in a box, Science (2022). DOI: 10.1126/science.abm2543.


Physicists report on first programmable quantum sensor
Mar 2022, phys.org

"In the development of quantum computers, we have learned to create tailored entangled states." 
("Custom Quantum", am I right?)

via University of Innsbruck: Christian Marciniak, Optimal metrology with programmable quantum sensors, Nature (2022). DOI: 10.1038/s41586-022-04435-4.

Also: Quantum Variational Optimization of Ramsey Interferometry and Atomic Clocks, Physical Review X (2021). DOI: 10.1103/PhysRevX.11.041045.


Chinese team breaks distance record for quantum secure direct communication
Apr 2022, phys.org

Distance of 102.2 km.
Prior to this new effort, the record was just 18 km.

via Tsinghua University in China: Haoran Zhang et al, Realization of quantum secure direct communication over 100 km fiber with time-bin and phase quantum states, Light: Science & Applications (2022). DOI: 10.1038/s41377-022-00769-w

Tying Quantum Knots - TU Delft - 2022

It takes three to tangle: Long-range quantum entanglement needs three-way interaction
May 2022, phys.org

The researchers' findings are consistent with previous observations that long-range entanglement survives at a non-zero temperature only when more than three subsystems are involved.

via RIKEN: Tomotaka Kuwahara et al, Exponential Clustering of Bipartite Quantum Entanglement at Arbitrary Temperatures, Physical Review X (2022). DOI: 10.1103/PhysRevX.12.021022


Tunable quantum traps for excitons
May 2022, phys.org

Physicists can now string together many such trapped excitons and adjust them in such a way that they emit photons having exactly the same properties. "That would allow one to create identical single photon sources for quantum information processing," 

via ETH Zurich: Deepankur Thureja et al, Electrically tunable quantum confinement of neutral excitons, Nature (2022). DOI: 10.1038/s41586-022-04634-z


Scientists use quantum computers to simulate quantum materials
May 2022, phys.org

"Computational Materials" sounds like another way of saying "active matter"?

Also "Hardware Noise":
Performing calculations of the properties of materials and molecules on quantum computers faces a problem that one does not experience with a classical computer, a phenomenon known as hardware noise. Noisy calculations return slightly different answers each time a calculation is performed; a noisy addition operation might return values slightly different from 4 each time for the question, "What is 2 plus 2?"

via Argonne National Laboratory's Midwest Integrated Center for Computational Materials and University of Chicago: Benchen Huang et al, Simulating the Electronic Structure of Spin Defects on Quantum Computers, PRX Quantum (2022). DOI: 10.1103/PRXQuantum.3.010339


Researchers achieve record entanglement of quantum memories
Jul 2022, phys.org

Again with the "quantum memories" term:
Researchers coupled two atomic quantum memories using two optically trapped rubidium atoms in two laboratories on the LMU campus connected via a 700-meter-long fiber optic cable.

via Ludwig Maximilian University of Munich: Tim van Leent et al, Entangling single atoms over 33 km telecom fibre, Nature (2022). DOI: 10.1038/s41586-022-04764-4


Scientists invent 'quantum flute' that can make particles of light move together
Jul 2022, phys.org

Ah yes, the quantum flute, we've been waiting for that one.

via University of Chicago: Srivatsan Chakram et al, Seamless High- Q Microwave Cavities for Multimode Circuit Quantum Electrodynamics, Physical Review Letters (2021). DOI: 10.1103/PhysRevLett.127.107701


Strange new phase of matter created in quantum computer acts like it has two time dimensions
Jul 2022, phys.org

First, the time thing:
By shining a laser pulse sequence inspired by the Fibonacci numbers at atoms inside a quantum computer, physicists have created a remarkable, never-before-seen phase of matter. The phase has the benefits of two time dimensions despite there still being only one singular flow of time, the physicists report July 20 in Nature.

Information stored in the phase is far more protected against errors than with alternative setups currently used in quantum computers. As a result, the information can exist without getting garbled for much longer, an important milestone for making quantum computing viable, says study lead author Philipp Dumitrescu.

The approach's use of an "extra" time dimension "is a completely different way of thinking about phases of matter."

Next, never seen this phrasing til now:
"stayed quantum"

via Simons Foundation: Philipp Dumitrescu, Dynamical topological phase realized in a trapped-ion quantum simulator, Nature (2022). DOI: 10.1038/s41586-022-04853-4


Researchers explore a new connection between topology and quantum entanglement
Aug 2022, phys.org

"Our work ties two big ideas together," says Charles Kane, the Christopher H. Browne Distinguished Professor of Physics in Penn's School of Arts & Sciences. "It's a conceptual link between topology, which is a way of characterizing the universal features that quantum states have, and entanglement, which is a way in which quantum states can exhibit non-local correlations, where something that happens in one point in space is correlated with something that happens in another part in space. What we've found is a situation where those concepts are tightly intertwined."
The eureka, and one of the pandemic sort:
The seed for exploring this connection came during the long hours Kane spent in his home office during the pandemic, pondering new ideas. One train of thought had him envisioning the classic textbook image of the Fermi surface of copper, which represents the metal's potential electron energies. It's a picture every physics student sees, and one with which Kane was highly familiar.

"Of course, I learned about that picture back in the 1980s but had never thought about it as describing a topological surface," Kane says. ...

via University of Pennsylvania: Pok Man Tam et al, Topological Multipartite Entanglement in a Fermi Liquid, Physical Review X (2022). DOI: 10.1103/PhysRevX.12.031022


Unexpected quantum effects in natural double-layer graphene
Aug 2022, phys.org

Again with the unexpected:
At temperatures just above absolute zero of minus 273.15 degrees Celsius, the electrons in the graphene can interact with each other—and a variety of complex quantum phases emerge completely unexpectedly. 

via University of Göttingen and University of Texas at Dallas: Anna M. Seiler et al, Quantum cascade of correlated phases in trigonally warped bilayer graphene, Nature (2022). DOI: 10.1038/s41586-022-04937-1


Post Script on the Sub- and Super-Luminal:
Listen to this guy Andrzej Dragan  talk about the "Quantum principle of relativity" at the Centrum Fizyki Teoretycznej, 2020-05-20

(the visuals come in at 19:40)