Cao et al. made lipid nanoparticles (LNPs) equipped with a small molecule ligand for blood-brain-barrier (BBB) 5-HT3 receptor and a cell penetrating peptide known as Tat. These LNPs crossed the BBB in mice more efficiently than control formulations.
Peptide-modified lipid nanoparticles enable systemic IL-12 mRNA delivery for glioblastoma treatment.
A paper-based, ingestible battery powered medical devices inside pigs for up to three days before gradually breaking down, a new study reported.
A tabletop experiment using a classical water vortex supports a decades-old theory describing the decay of turbulence in quantum fluids.
When you pull the plug at the end of a relaxing bath, a vortex forms as water drains through the plughole. If you watch carefully, the slender whirlpool may begin to wobble, with helical, corkscrew-like disturbances traveling along its length. In 1880, William Thomson, who later became Lord Kelvin, showed mathematically that a straight vortex filament can support such helical waves [1]. Today, Kelvin waves are thought to hold the key to one of the outstanding puzzles of quantum turbulence: how the kinetic energy of an agitated quantum fluid is ultimately dissipated. Now Eric Falcon of Paris Cité University and his colleagues have directly observed Kelvin-wave turbulence using a vortex no more exotic than one found in a bathtub [2].
Kelvin waves are particularly important in superfluids, ultracold atomic gases, and the interiors of neutron stars. Rather than being spread throughout the fluid, superfluid vorticity is confined to thin, line-like topological defects, each carrying a fixed quantum of circulation (Fig. 1) [3]. A tangle of these so-called quantum vortices forms quantum turbulence—“superfluid spaghetti”—first envisaged by Richard Feynman in the 1950s [4]. This picture raises a fundamental question about the fate of the energy stored in the vortex tangle. In classical turbulence, energy cascades to small scales where it is dissipated by viscosity. But an ultracold superfluid is inviscid. How, then, does turbulent motion in a superfluid eventually decay?
Researchers in China have extended the lifetime of entanglement in a room-temperature, solid-state system by up to a factor of 240. Led by Shuo Ren and Rui-Jian Liang at the University of Science and Technology of China in Hefei, the team transferred entangled states from the electron spins of solid-state defects to the spins of surrounding atomic nuclei, which are far more resilient to noise. The research has been published in Physical Review Letters.
When two or more quantum particles are entangled, their properties remain correlated no matter how far apart they are: Measuring one immediately tells you something about its entangled partners. This phenomenon is increasingly being explored for quantum sensing and information processing, where entangled networks of quantum bits, or “qubits,” can perform tasks beyond the limits of classical systems.
The enduring challenge is that quantum information is quickly destroyed as qubits interact with thermal fluctuations in their surroundings. This noise can be minimized by cooling systems to ultracold temperatures—but today, physicists are also exploring more practical approaches, in which qubits have built-in resilience against their environment while still allowing information to be easily written and read out.
The electronic properties of materials are typically determined by their structure under normal, undisturbed conditions, when they are in a state known as equilibrium. Intense light beams, however, can temporarily reshape a material’s electronic band structure (i.e., the range of energy states available to electrons), potentially giving rise to new electronic behaviors.
Researchers at Friedrich-Alexander University Erlangen-Nürnberg, Ludwig Maximilian University of Munich, the Technion—Israel Institute of Technology, and the University of Central Florida recently demonstrated that illuminating graphene with a specific type of light temporarily modifies its electron states, prompting the emergence of a so-called Floquet topological insulator.
This is a transient, out-of-equilibrium state created when a periodically oscillating field reshapes a material’s electronic structure, resulting in topological properties that are absent at equilibrium.
Quantum key distribution allows two users to establish secret keys whose security is grounded in the laws of quantum mechanics. Extending this capability to multiple users is an essential step toward quantum networks that support secure communication among many participants. Quantum cryptographic conferencing addresses this need by enabling multiple users to share the same secure key, which they can then use to protect group communications.
In an article published in Physical Review Letters, a team led by professor Xiao-Song Ma at Nanjing University reports the experimental realization of asynchronous measurement-device-independent quantum cryptographic conferencing, or AMDI QCC. The demonstration addresses two major challenges in developing practical quantum networks: maintaining useful key-generation rates as networks grow and reducing the complexity of controlling optical phases.
As illustrated above, three users independently send optical pulses to a shared GHZ measurement station, where a fiber-based multipath interferometer enables interference between signals from different users and single-photon detection.
Ultrashort laser pulses can be used to generate X-rays. Normally, however, only certain specific frequencies are produced. A team from TU Wien and the University of California San Diego has developed a method that makes it possible to tune the frequency continuously.
Using a six-meter-long gas-filled waveguide (20 feet long) containing the appropriate gas, the researchers can “detune” the light frequencies so that, in the end, exactly the required X-ray frequency is produced. The results have been published in the journal Communications Physics.
Photonic integrated circuits route information with optical signals instead of relying only on electrical currents. Silicon (Si) and silicon nitride (SiNx) are excellent photonic platforms for waveguides, but they cannot efficiently perform the ever-increasing tasks required for fully integrated optical systems. A heterogeneous photonic integration platform capable of interfacing different optical materials with high performance is thus an ongoing challenge for both academia and industry.
Conventional approaches use heteroepitaxy to realize thin-film functional materials on target optical substrates. However, this method confronts fundamental challenges in lattice matching and process compatibility, and substantially deteriorated epilayer material quality is often observed in mismatched photonic chips.
In our recent work published in Nature, a group of researchers from Washington University in St. Louis (WUSTL), the Swiss Federal Institute of Technology Lausanne (EPFL), and the Massachusetts Institute of Technology (MIT) demonstrated a different strategy: preparing desired thin-film materials on their most suitable parent substrates, then delaminating them into freestanding single-crystalline nanomembranes for unbridled heterogeneous photonic integration on arbitrary photonic templates.
Before diving into the mystery of glass, theoretical physicist Corentin Laudicina takes us back to high school physics for a moment. Although he has spent years studying exactly what happens in a material during the glass transition, he also understands that his research is not the easiest thing to explain off the cuff at the cafeteria table.
According to school textbooks, matter can exist in three different states: gas, liquid and solid. Think of water vapor, liquid water and ice. The molecules that make up the material are the same, but the way they can move differs greatly, Laudicina explains.
He pulls out his dissertation and shows a figure from the introductory chapter. “The higher the temperature, the more freely the molecules can move. In a solid, they are arranged in a crystal lattice—in a fixed position, at a fixed distance from one another—but in a liquid, they can move without having a fixed position relative to each other. In the gas phase, those movements are even freer.”