In this issue: Biocompatible Carbon, Quantum Lego, A Microscopic View of Cracking
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Biocompatible Carbon
Simulations show that lipid membranes called liposomes can be used as biocompatible solvents for carbon nanoparticles in medical applications.
C60 fullerenes, aka buckyballs, are being investigated for applications in nanomedicine, from drug delivery vectors to diagnostic contrast agents. Their use faces an important challenge: there are few solvents for fullerenes that are nontoxic and biocompatible. Recent work has shown that liposomes (vesicles made of lipid bilayers) may be an efficient fullerene solvent, but little is known on how to design optimal fullerene-carrying liposomes. Now, a research team in France has presented simulations that explain how liposomes dissolve fullerene clusters and suggest they may be regarded as biocompatible solvents that can be chemically tuned to specific medical applications.
* J Barnoud, G Rossi, Luca Monticelli (contact author), “Lipid membranes as solvents for carbon nanoparticles”, Physical Review Letters (expected publication date: Feb 12)
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Quantum Lego
Theorists have proposed a modular design for quantum computers that can be used to assemble large numbers of qubits into a fault-tolerant device.
A major challenge of quantum computing is the assembly of individual qubits into an actual working device: a large number of logic elements need to communicate over data channels while preserving the fragile entanglement between qubits that is the basis of any quantum advantage. A team of researchers from the US, Canada and China has confronted this problem with a proposed modular quantum computing design that is scalable to a large number of qubits while remaining fault tolerant. The scheme is based on building blocks made of arrays of trapped ions controlled with optical or microwave pulses and connected via optical fibers.
* C Monroe, Jungsang Kim (contact author), “Large Scale Modular Quantum Computer Architecture with Atomic Memory and Photonic Interconnects”, Physical Review A (expected publication date: Feb 13)
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A Microscopic View of Cracking
A new microscopic model describes how porous materials such as sandstone break, providing good agreement with the behavior observed in experiments.
Modeling the catastrophic failure of materials has a wide range of applications, from earthquake science to civil engineering. The description of such fracture processes is complicated by the fact that microscopic cracks can propagate all the way up to the size of mountains. As a consequence, most currently used models are too simplistic to connect to experiments. A team of researchers from Hungary and Scotland presents an improved model of cracking in a porous material (such as sedimentary rock), which better describes the microscopic material structure. They found that cracks spread through the material in cascading avalanches that happen at erratic intervals, separated by quiescent periods. Their model can reproduce well the complex behavior observed in experiments, including many features of cracking deduced from measurements of the sound waves that accompany the propagation of cracks.
* Ferenc Kun (contact author), I Varga, S Lennartz-Sassinek, IG Main, Physical Review Letters (expected publication date:Feb 14)
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Journal articles and preprints are available to journalists on request.
Matteo Rini, PhD
Deputy Editor, Physics
