Lifeboat Foundation

Using numerical modelling, researchers from Russia, the US, and China have discovered previously unknown features of rutile TiO2, which is a promising photocatalyst. The calculations were performed at an MIPT laboratory on the supercomputer Rurik. A paper detailing the results has been published in the journal Physical Chemistry Chemical Physics.

It’s all on the surface

Special substances called catalysts are needed to accelerate or induce certain chemical reactions. Titanium dioxide (TiO2) is a good photocatalyst—when exposed to light, it effectively breaks down water molecules as well as hazardous organic contaminants. TiO2 is naturally found in the form of rutile and other minerals. One of the two most active surfaces of rutile R-TiO2 is a surface that is denoted as (011). The photocatalytic activity is linked to the way in which oxygen and titanium atoms are arranged on the surface. This is why it is important to understand which forms the surface of rutile can take.

A high-tech version of an old-fashioned balance scale at the National Institute of Standards and Technology (NIST) has just brought scientists a critical step closer toward a new and improved definition of the kilogram. The scale, called the NIST-4 watt balance, has conducted its first measurement of a fundamental physical quantity called Planck’s constant to within 34 parts per billion — demonstrating the scale is accurate enough to assist the international community with the redefinition of the kilogram, an event slated for 2018.

The redefinition-which is not intended to alter the value of the kilogram’s mass, but rather to define it in terms of unchanging fundamental constants of nature-will have little noticeable effect on everyday life. But it will remove a nagging uncertainty in the official kilogram’s mass, owing to its potential to change slightly in value over time, such as when someone touches the metal artifact that currently defines it.

Planck’s constant lies at the heart of quantum mechanics, the theory that is used to describe physics at the scale of the atom and smaller. Quantum mechanics began in 1900 when Max Planck described how objects radiate energy in tiny packets known as “quanta.” The amount of energy is proportional to a very small quantity called h, known as Planck’s constant, which subsequently shows up in almost all equations in quantum mechanics. The value of h — according to NIST’s new measurement — is 6.62606983×10−34 kg?m2/s, with an uncertainty of plus or minus 22 in the last two digits.

Robert Dunleavy had just started his sophomore year at Lehigh University when he decided he wanted to take part in a research project. He sent an email to Bryan Berger, an assistant professor of chemical and biomolecular engineering, who invited Dunleavy to his lab.

Berger and his colleagues were conducting experiments on tiny semiconductor particles called quantum dots. The optical and electronic properties of QDs make them useful in lasers, light-emitting diodes (LEDs), medical imaging, solar cells, and other applications.

Dunleavy joined Berger’s group and began working with cadmium sulfide (CdS), one of the compounds from which QDs are fabricated. The group’s goal was to find a better way of producing CdS quantum dots, which are currently made with toxic chemicals in an expensive process that requires high pressure and temperature.

Continue reading “Using Enzymes to Enhance LEDs” »

This is excellent; being able to ensuring that 2 particles can act as 1 molecule through tunneling.

Researchers have theoretically shown that in certain conditions, two particles will begin to act as if they are one molecule and undergo quantum tunneling together.

Nice.

Richard Feynman suggested that it takes a quantum computer to simulate large quantum systems, but a new study shows that a classical computer can work when the system has loss and noise.

The field of quantum computing originated with a question posed by Richard Feynman. He asked whether or not it was feasible to simulate the behavior of quantum systems using a classical computer, suggesting that a quantum computer would be required instead [1]. Saleh Rahimi-Keshari from the University of Queensland, Australia, and colleagues [2] have now demonstrated that a quantum process that was believed to require an exponentially large number of steps to simulate on a classical computer could in fact be simulated in an efficient way if the system in which the process occurs has sufficiently large loss and noise.

Continue reading “Viewpoint: Classical Simulation of Quantum Systems?” »

(Phys.org)—A team of researchers with the Pohang University of Science and Technology in Korea has created organic nanowire synaptic transistors that emulate the working principles of biological synapses. As they describe in their paper published in the journal Science Advances, the artificial synapses they have created use much smaller amounts of power than other devices developed thus far and rival that of their biological counterparts.

Scientists are taking multiple paths towards building next generation computers—some are fixated on finding a material to replace silicon, others are working towards building a quantum machine, while still others are busy trying to build something much more like the human mind. A hybrid system of sorts that has organic artificial parts meant to mimic those found in the brain. In this new effort, the team in Korea has reached a new milestone in creating an artificial synapse—one that has very nearly the same power requirements as those inside our skulls.

Up till now, artificial synapses have consumed far more power than human synapses, which researchers have calculated is on the order of 10 femtojoules each time a single one fires. The new synapse created by the team requires just 1.23 femtojoules per event—far lower than anything achieved thus far, and on par with their natural rival. Though it might seem the artificial creations are using less power, they do not perform the same functions just yet, so natural biology is still ahead. Plus there is the issue of transferring information from one neuron to another. The “wires” used by the human body are still much thinner than the metal kind still being used by scientists—still, researchers are gaining.

Continue reading “Researchers create organic nanowire synaptic transistors that emulate the working principles of biological synapses” »

Scientists from the UK used gold to trap photons with a molecule at room temperature. The experiment shows evidence of the quantum nature of light.

It’s a Trap!

A group of physicists from the UK were able to mix light and molecules at room temperature. This phenomenon is called strong coupling. It has been achieved before, but only at very low temperatures. Achieving this at room temperature makes it easier to manipulate the process and to do experiments at lower costs.

Continue reading “Part Light, Part Matter: Physicists Create ‘Mixed Matter’ at Room Temperature” »

Although I shared an article last week about this new record being acheived; this version of the story seems to have some additional insights.

A recent experiment could open new doors in space-based quantum communication.

Spectroscopy studies of charge transfer from cadmium selenide quantum dots to molecular nickel catalysts reveal unexpectedly fast electron transfer, enabling exceptional photocatalytic hydrogen production.

A key challenge facing the US is the harvesting, production, storage, and distribution of energy to support economic prosperity with responsible environmental management. Currently, fossil fuels provide more than 80% of the energy consumed in the US (even when significant increases in the use of alternative sources of energy in recent years are accounted for).¹ For the US Department of Defense in particular, volatility in the price and availability of fossil fuels leads to significant short- and long-term financial, operational, and strategic risks.² There is, therefore, clearly a need for new alternative sources of energy.

Continue reading “Ultrafast dynamics of semiconductor nanocrystals” »