Tag Archives: quantum mechanics

Violating the 2nd law of thermodynamics—temporarily—at the nanoscale

For anyone unfamiliar with the laws of thermodynamics or anyone who enjoys some satire with their music, here’s the duo of Flanders & Swann with the ‘First and Second Law’ in a 1964 performance,

According to a March 31, 2014 news item on Nanowerk, it seems, contrary to scientific thought and Flanders & Swann, the 2nd law can be violated, for a time, albeit at the nanoscale,

Objects with sizes in the nanometer range, such as the molecular building blocks of living cells or nanotechnological devices, are continuously exposed to random collisions with surrounding molecules. In such fluctuating environments the fundamental laws of thermodynamics that govern our macroscopic world need to be rewritten. An international team of researchers from Barcelona, Zurich and Vienna found that a nanoparticle trapped with laser light temporarily violates the famous second law of thermodynamics, something that is impossible on human time and length scale.

A March 31, 2014 University of Vienna news release on EurekAlert, which originated the news item, describes the 2nd law and gives details about the research,

Watching a movie played in reverse often makes us laugh because unexpected and mysterious things seem to happen: glass shards lying on the floor slowly start to move towards each other, magically assemble and suddenly an intact glass jumps on the table where it gently gets to a halt. Or snow starts to from a water puddle in the sun, steadily growing until an entire snowman appears as if molded by an invisible hand. When we see such scenes, we immediately realize that according to our everyday experience something is out of the ordinary. Indeed, there are many processes in nature that can never be reversed. The physical law that captures this behavior is the celebrated second law of thermodynamics, which posits that the entropy of a system – a measure for the disorder of a system – never decreases spontaneously, thus favoring disorder (high entropy) over order (low entropy).

However, when we zoom into the microscopic world of atoms and molecules, this law softens up and looses its absolute strictness. Indeed, at the nanoscale the second law can be fleetingly violated. On rare occasions, one may observe events that never happen on the macroscopic scale such as, for example heat transfer from cold to hot which is unheard of in our daily lives. Although on average the second law of thermodynamics remains valid even in nanoscale systems, scientists are intrigued by these rare events and are investigating the meaning of irreversibility at the nanoscale.

Recently, a team of physicists of the University of Vienna, the Institute of Photonic Sciences in Barcelona and the Swiss Federal Institute of Technology in Zürich succeeded in accurately predicting the likelihood of events transiently violating the second law of thermodynamics. They immediately put the mathematical fluctuation theorem they derived to the test using a tiny glass sphere with a diameter of less than 100 nm levitated in a trap of laser light. Their experimental set-up allowed the research team to capture the nano-sphere and hold it in place, and, furthermore, to measure its position in all three spatial directions with exquisite precision. In the trap, the nano-sphere rattles around due to collisions with surrounding gas molecules. By a clever manipulation of the laser trap the scientists cooled the nano-sphere below the temperature of the surrounding gas and, thereby, put it into a non-equilibrium state. They then turned off the cooling and watched the particle relaxing to the higher temperature through energy transfer from the gas molecules. The researchers observed that the tiny glass sphere sometimes, although rarely, does not behave as one would expect according to the second law: the nano-sphere effectively releases heat to the hotter surroundings rather than absorbing the heat. The theory derived by the researchers to analyze the experiment confirms the emerging picture on the limitations of the second law on the nanoscale.

Given the theoretical descriptions of the applications mentioned in the news release, it sounds like at least one of them might be a ‘quantum computing project’,

The experimental and theoretical framework presented by the international research team in the renowned scientific journal Nature Nanotechnology has a wide range of applications. Objects with sizes in the nanometer range, such as the molecular building blocks of living cells or nanotechnological devices, are continuously exposed to a random buffeting due to the thermal motion of the molecules around them. As miniaturization proceeds to smaller and smaller scales nanomachines will experience increasingly random conditions. Further studies will be carried out to illuminate the fundamental physics of nanoscale systems out of equilibrium. The planned research will be fundamental to help us understand how nanomachines perform under these fluctuating conditions.

Here’s a link to and a citation for the paper,

Dynamic Relaxation of a Levitated Nanoparticle from a Non-Equilibrium Steady State by Jan Gieseler, Romain Quidant, Christoph Dellago, and Lukas Novotny. Nature Nanotechnology AOP, February 28, 2014. DOI: 10.1038/NNANO.2014.40

The paper is behind a paywall but a free preview is available via ReadCube access.

Fundamental mechanical behaviour of cellulose nanocrystals (aka nanocrystalline cellulose)

Emil Venere at Purdue University offers an excellent explanation of why there’s so much international interest in cellulose nanocrystals (CNC aka, nanocrystalline cellulose [NCC]) in his Dec. 16, 2013 Purdue University (Indiana, US) news release (also on EurekAlert), Note: A link has been removed,

The same tiny cellulose crystals that give trees and plants their high strength, light weight and resilience, have now been shown to have the stiffness of steel.

The nanocrystals might be used to create a new class of biomaterials with wide-ranging applications, such as strengthening construction materials and automotive components.

Calculations using precise models based on the atomic structure of cellulose show the crystals have a stiffness of 206 gigapascals, which is comparable to steel, said Pablo D. Zavattieri, a Purdue University assistant professor of civil engineering.

Here’s an image of the cellulose crystals being examined,

This transmission electron microscope image shows cellulose nanocrystals, tiny structures that give trees and plants their high strength, light weight and resilience. The nanocrystals might be used to create a new class of biomaterials that would have a wide range of applications. (Purdue Life Sciences Microscopy Center)

This transmission electron microscope image shows cellulose nanocrystals, tiny structures that give trees and plants their high strength, light weight and resilience. The nanocrystals might be used to create a new class of biomaterials that would have a wide range of applications. (Purdue Life Sciences Microscopy Center)

You’ll notice this image is not enhanced and made pretty as compared to the images in my Dec. 16, 2013 posting about Bristol University’s Art of Science competition. It takes a lot of work to turn the types of images scientists use into ‘art’.

Getting back to the CNC, this news release was probably written by someone who’s not familiar with the other work being done in the field (university press officers typically write about a wide range of topics and cannot hope to have in depth knowledge on each topic) and so it’s being presented as if it is brand new information. In fact, there has been several years work done in five other national jurisdictions that I know of (Sweden, Finland, Canada, Brazil, and Israel) and there are likely more. That’s not including other US states pursuing research in this area, notably Wisconsin.

What I (taking into account  my limitations) find particularly exciting in this work is the detail they’ve been able to determine and the reference to quantum mechanics. Here’s more from the news release (Note: Links have been removed),

“It is very difficult to measure the properties of these crystals experimentally because they are really tiny,” Zavattieri said. “For the first time, we predicted their properties using quantum mechanics.”

The nanocrystals are about 3 nanometers wide by 500 nanometers long – or about 1/1,000th the width of a grain of sand – making them too small to study with light microscopes and difficult to measure with laboratory instruments.

The findings represent a milestone in understanding the fundamental mechanical behavior of the cellulose nanocrystals.

“It is also the first step towards a multiscale modeling approach to understand and predict the behavior of individual crystals, the interaction between them, and their interaction with other materials,” Zavattieri said. “This is important for the design of novel cellulose-based materials as other research groups are considering them for a huge variety of applications, ranging from electronics and medical devices to structural components for the automotive, civil and aerospace industries.”

From an applications perspective (which is what excites so much international interest),

The cellulose nanocrystals represent a potential green alternative to carbon nanotubes for reinforcing materials such as polymers and concrete. Applications for biomaterials made from the cellulose nanocrystals might include biodegradable plastic bags, textiles and wound dressings; flexible batteries made from electrically conductive paper; new drug-delivery technologies; transparent flexible displays for electronic devices; special filters for water purification; new types of sensors; and computer memory.

Cellulose could come from a variety of biological sources including trees, plants, algae, ocean-dwelling organisms called tunicates, and bacteria that create a protective web of cellulose.

“With this in mind, cellulose nanomaterials are inherently renewable, sustainable, biodegradable and carbon-neutral like the sources from which they were extracted,” Moon said. “They have the potential to be processed at industrial-scale quantities and at low cost compared to other materials.”

Biomaterials manufacturing could be a natural extension of the paper and biofuels industries, using technology that is already well-established for cellulose-based materials.

“Some of the byproducts of the paper industry now go to making biofuels, so we could just add another process to use the leftover cellulose to make a composite material,” Moon said. “The cellulose crystals are more difficult to break down into sugars to make liquid fuel. So let’s make a product out of it, building on the existing infrastructure of the pulp and paper industry.”

Their surface can be chemically modified to achieve different surface properties.

“For example, you might want to modify the surface so that it binds strongly with a reinforcing polymer to make a new type of tough composite material, or you might want to change the chemical characteristics so that it behaves differently with its environment,” Moon said.

Zavattieri plans to extend his research to study the properties of alpha-chitin, a material from the shells of organisms including lobsters, crabs, mollusks and insects. Alpha-chitin appears to have similar mechanical properties as cellulose.

“This material is also abundant, renewable and waste of the food industry,” he said.

Here’s a link to and a citation for the paper,

Anisotropy of the Elastic Properties of Crystalline Cellulose Iβ from First Principles Density Functional Theory with Van der Waals Interactions by Fernando L. Dri, Louis G. Hector Jr., Robert J. Moon, Pablo D. Zavattieri.  Cellulose December 2013, Volume 20, Issue 6, pp 2703-2718. 10.1007/s10570-013-0071-8

This paper is behind a paywall although you can preview the first few pages.

Casimir and its reins: engineering nanostructures to control quantum effects

Thank you to whomever wrote this headline for the Oct. 22, 2013 US National Institute of Standards and Technology (NIST) news release, also on EurekAlert, titled: The Reins of Casimir: Engineered Nanostructures Could Offer Way to Control Quantum Effect … Once a Mystery Is Solved, for getting the word ‘reins’ correct.

I can no longer hold back my concern over the fact that there are three words that sound the same but have different meanings and one of those words is often mistakenly used in place of the other.

reins

reigns

rains

The first one, reins, refers to narrow leather straps used to control animals (usually horses), as per this picture, It’s also used as a verb to indicate situation where control must be exerted, e.g., the spending must be reined in.

Reining Sliding Stop Mannheim Maimarkt 2007 Date 01.05.2007 Source  Own work Author AllX [downloaded from http://en.wikipedia.org/wiki/File:Reining_slidingstop.jpg]

Reining Sliding Stop Mannheim Maimarkt 2007 Date 01.05.2007 Credit: AllX [downloaded from http://en.wikipedia.org/wiki/File:Reining_slidingstop.jpg]

 This ‘reign’ usually references people like these,

“Queen Elizabeth II greets employees on her walk from NASA’s Goddard Space Flight Center mission control to a reception in the center’s main auditorium in Greenbelt, Maryland where she was presented with a framed Hubble image by Congressman Steny Hoyer and Senator Barbara Mikulski. Queen Elizabeth II and her husband, Prince Philip, Duke of Edinburgh, visited the NASA Goddard Space Flight Center as one of the last stops on their six-day United States visit.” Credit: NASA/Bill Ingalls [downloaded from http://en.wikipedia.org/wiki/File:Elizabeth_II_greets_NASA_GSFC_employees,_May_8,_2007_edit.jpg]

“Queen Elizabeth II greets employees on her walk from NASA’s Goddard Space Flight Center mission control to a reception in the center’s main auditorium in Greenbelt, Maryland where she was presented with a framed Hubble image by Congressman Steny Hoyer and Senator Barbara Mikulski. Queen Elizabeth II and her husband, Prince Philip, Duke of Edinburgh, visited the NASA Goddard Space Flight Center as one of the last stops on their six-day United States visit.” Credit: NASA/Bill Ingalls [downloaded from http://en.wikipedia.org/wiki/File:Elizabeth_II_greets_NASA_GSFC_employees,_May_8,_2007_edit.jpg]

 And,

Thailand's King Bhumibol Adulyadej waves to well-wishers during a concert at Siriraj hospital in Bangkok on September 29, 2010. Credit: Government of Thailand [downloaded from http://en.wikipedia.org/wiki/File:King_Bhumibol_Adulyadej_2010-9-29.jpg]

Thailand’s King Bhumibol Adulyadej waves to well-wishers during a concert at Siriraj hospital in Bangkok on September 29, 2010. Credit: Government of Thailand [downloaded from http://en.wikipedia.org/wiki/File:King_Bhumibol_Adulyadej_2010-9-29.jpg]

Kings, Queens, etc. reign over or rule their subjects or they have reigns, i.e., the period during which they hold the position of queen/king, etc. There are also uses such as this one found in the song title ‘Love Reign O’er Me’ (Pete Townshend)

I’ve lost count of the times I’ve seen ‘reigns’ used in place of ‘reins’, the worst part being? I’ve caught myself making the mistake. So, a heartfelt thank you to the NIST news release writer for getting it right. As for the other ‘rains’, neither I not anyone else seems to make that mistake (so far as I’ve seen).

Now on to the news,

You might think that a pair of parallel plates hanging motionless in a vacuum just a fraction of a micrometer away from each other would be like strangers passing in the night—so close but destined never to meet. Thanks to quantum mechanics, you would be wrong.

Scientists working to engineer nanoscale machines know this only too well as they have to grapple with quantum forces and all the weirdness that comes with them. These quantum forces, most notably the Casimir effect, can play havoc if you need to keep closely spaced surfaces from coming together.

Controlling these effects may also be necessary for making small mechanical parts that never stick to each other, for building certain types of quantum computers, and for studying gravity at the microscale.

In trying to solve the problem of keeping closely spaced surfaces from coming together, the scientists uncovered another problem,

One of the insights of quantum mechanics is that no space, not even outer space, is ever truly empty. It’s full of energy in the form of quantum fluctuations, including fluctuating electromagnetic fields that seemingly come from nowhere and disappear just as fast.

Some of this energy, however, just isn’t able to “fit” in the submicrometer space between a pair of electromechanical contacts. More energy on the outside than on the inside results in a kind of “pressure” called the Casimir force, which can be powerful enough to push the contacts together and stick.

Prevailing theory does a good job describing the Casimir force between featureless, flat surfaces and even between most smoothly curved surfaces. However, according to NIST researcher and co-author of the paper, Vladimir Aksyuk, existing theory fails to predict the interactions they observed in their experiment.

“In our experiment, we measured the Casimir attraction between a gold-coated sphere and flat gold surfaces patterned with rows of periodic, flat-topped ridges, each less than 100 nanometers across, separated by somewhat wider gaps with deep sheer-walled sides,” says Aksyuk. “We wanted to see how a nanostructured metallic surface would affect the Casimir interaction, which had never been attempted with a metal surface before. Naturally, we expected that there would be reduced attraction between our grooved surface and the sphere, regardless of the distance between them, because the top of the grooved surface presents less total surface area and less material. However, we knew the Casimir force’s dependence on the surface shape is not that simple.”

Indeed, what they found was more complicated.

According to Aksyuk, when they increased the separation between the surface of the sphere and the grooved surface, the researchers found that the Casimir attraction decreased much more quickly than expected. When they moved the sphere farther away, the force fell by a factor of two below the theoretically predicted value. When they moved the sphere surface close to the ridge tops, the attraction per unit of ridge top surface area increased.

“Theory can account for the stronger attraction, but not for the too-rapid weakening of the force with increased separation,” says Aksyuk. “So this is new territory, and the physics community is going to need to come up with a new model to describe it.”

For the curious, here’s a link to and a citation for the research paper,

Strong Casimir force reduction through metallic surface nanostructuring by Francesco Intravaia, Stephan Koev, Il Woong Jung, A. Alec Talin, Paul S. Davids, Ricardo S. Decca, Vladimir A. Aksyuk, Diego A. R. Dalvit, & Daniel López. Nature Communications 4, Article number: 2515 doi:10.1038/ncomms3515 Published 27 September 2013.

This article is open access.

Testing ‘Schroedinger’s cat’ on everyday objects at the University of Calgary (Canada)

For decades physicists have been grappling with the question of why the rules for quantum mechanics/physics are so different from classical physics while they try to unify the theories into one coherent explanation for why things are the way they are. At the same time, they’ve also been trying to test how the rules of quantum mechanics might apply to everyday objects and it seems a team from the University of Calgary (Alberta, Canada) have made a breakthrough.

The July 21, 2013 University of Calgary news release on EurekAlert provides an explanation of Schroedinger’s thought experiment (the dead/alive cat), quantum mechanics, and difficulties testing the theory on everyday objects thus helping those of us without that knowledge to better understand the breakthrough,

In contrast to our everyday experience, quantum physics allows for particles to be in two states at the same time — so-called quantum superpositions. A radioactive nucleus, for example, can simultaneously be in a decayed and non-decayed state.

Applying these quantum rules to large objects leads to paradoxical and even bizarre consequences. To emphasize this, Erwin Schroedinger, one of the founding fathers of quantum physics, proposed in 1935 a thought experiment involving a cat that could be killed by a mechanism triggered by the decay of a single atomic nucleus. If the nucleus is in a superposition of decayed and non-decayed states, and if quantum physics applies to large objects, the belief is that the cat will be simultaneously dead and alive.

While quantum systems with properties akin to ‘Schroedinger’s cat’ have been achieved at a micro level, the application of this principle to everyday macro objects has proved to be difficult to demonstrate.

“This is because large quantum objects are extremely fragile and tend to disintegrate when subjected to any interaction with the environment,” explains Lvovsky [professor Alex Lvovsky].

Now for the breakthrough (from the news release),

The breakthrough achieved by Calgary quantum physicists is that they were able to contrive a quantum state of light that consists of a hundred million light quanta (photons) and can even be seen by the naked eye. In their state, the “dead” and “alive” components of the “cat” correspond to quantum states that differ by tens of thousands of photons.

“The laws of quantum mechanics which govern the microscopic world are very different from classical physics that rules over large objects such as live beings,” explains lead author Lvovsky. “The challenge is to understand where to draw the line and explore whether such a line exists at all. Those are the questions our experiment sheds light on,” he states.

While the findings are promising, study co-author Simon [professor Christoph Simon] admits that many questions remain unanswered.

“We are still very far from being able to do this with a real cat,” he says. “But this result suggests there is ample opportunity for progress in that direction.”

They want to try this on a real live  cat? hmmm

For those who’d like to satisfy their curiosity further, here’s a link to and a citation for the published paper,

Observation of micro–macro entanglement of light by A. I. Lvovsky, R. Ghobadi, A. Chandra, A. S. Prasad & C. Simon. Nature Physics (2013) doi:10.1038/nphys2682 Published online 21 July 2013

This paper is behind a paywall.

The best atomic movie ever from the University of Toronto (Canada)

To date, the real-time video, recorded by scientists from the University of Toronto, of atoms undergoing a transformation to become a new structure offers the best resolution yet, according to an Apr. 18, 2013 news item on Azonano,

“It’s the first look at how chemistry and biology involve just a few key motions for even the most complex systems,” says U of T [University of Toronto] chemistry and physics professor R. J. Dwayne Miller, principal investigator of the study. “There is an enormous reduction in complexity at the defining point, the transition state region, which makes chemical processes transferrable from one type of molecule to another. This is how new drugs or materials are made.”

Miller, who holds a joint appointment as director of the Max Planck Research Group for Structural Dynamics at the Centre for Free Electron Laser Science, conducted the research with colleagues from institutions in Germany and Japan. He says nature uses this reduction principle at transition states to breathe life into otherwise inanimate matter.

“The first atomic movies were very grainy, much like the first motion pictures,” says Miller. “The new movies are so clear one could dare say they are becoming beautiful to behold, especially when you remember you are looking at atoms moving on the fly. We’ve captured them at an incredibly fast rate of less than 1 millionth of a millionth of a second per frame.”

In the Apr. 17, 2013 University of Toronto news release, which originated the news item, Miller provides a description of the complexity,

To help illuminate what’s going on here,  Miller explains that with two atoms there is only one possible coordinate or dimension for following the chemical pathway. With three atoms, two dimensions are now needed. However, with a complex molecule, it would be expected that hundreds or even thousands of dimensions would be required to map all possible trajectories of the atoms.

“In this case, chemistry would be a completely new problem for every molecule,” says Miller. “But somehow there is an enormous reduction in dimensions to just a few motions, and we are now able to see exactly how this works at the atomic level of detail.”

Mapping molecular motions -- the "magic" of Chemistry revealed. Despite the enormous number of possible arrangements of atoms during a structural transition, such as occurs with changes in charge distribution or chemical processes, the interconversion from one structure to another reduces to a few key types of motions.  This enormous reduction in dimensionality is what makes chemical concepts transferable from one molecule to another and has enabled chemists to synthesize nearly any molecule desired, for new drugs to infusing new material properties. This movie gives a direct atomic level view of this enormous reduction in complexity.  The specific trajectories along 3 different coordinates, as highlighted in the movie, are shown as projections (right view) on a cube.  The key atomic motions can be mapped on to 3 highly simplified coordinates -- the magic of chemistry in its full atomic splendour. Credit: Lai Chung Liu, University of Toronto

Mapping molecular motions — the “magic” of Chemistry revealed. Despite the enormous number of possible arrangements of atoms during a structural transition, such as occurs with changes in charge distribution or chemical processes, the interconversion from one structure to another reduces to a few key types of motions. This enormous reduction in dimensionality is what makes chemical concepts transferable from one molecule to another and has enabled chemists to synthesize nearly any molecule desired, for new drugs to infusing new material properties. This movie gives a direct atomic level view of this enormous reduction in complexity. The specific trajectories along 3 different coordinates, as highlighted in the movie, are shown as projections (right view) on a cube. The key atomic motions can be mapped on to 3 highly simplified coordinates — the magic of chemistry in its full atomic splendour.
Credit: Lai Chung Liu, University of Toronto

Unfortunately, I was not able to successfully bring over the movie but you can try accessing it from here.

Mechanics of quantum kissing

“It is as if you can kiss without quite touching lips,” says Professor Jeremy Baumberg from the University of Cambridge Cavendish Laboratory in the University of Cambridge’s Nov. 7, 2012 news release about quantum electron jumps,

Even empty gaps have a colour. Now scientists have shown that quantum jumps of electrons can change the colour of gaps between nano-sized balls of gold. The new results, published today in the journal Nature, set a fundamental quantum limit on how tightly light can be trapped.

The team from the Universities of Cambridge, the Basque Country and Paris have combined tour de force experiments with advanced theories to show how light interacts with matter at nanometre sizes. The work shows how they can literally see quantum mechanics in action in air at room temperature.

As for the kissing, it all starts with metal and jumping electrons,

Because electrons in a metal move easily, shining light onto a tiny crack pushes electric charges onto and off each crack face in turn, at optical frequencies. The oscillating charge across the gap produces a ‘plasmonic’ colour for the ghostly region in-between, but only when the gap is small enough.

Team leader Professor Jeremy Baumberg from the University of Cambridge Cavendish Laboratory suggests we think of this like the tension building between a flirtatious couple staring into each other’s eyes. As their faces get closer the tension mounts, and only a kiss discharges this energy.

H/T to the Nov. 7, 2012 news item on ScienceDaily where I first learned of quantum kissing,

In the new experiments, the gap is shrunk below 1nm (1 billionth of a metre) which strongly reddens the gap colour as the charge builds up. However because electrons can jump across the gap by quantum tunnelling, the charge can drain away when the gap is below 0.35nm, seen as a blue-shifting of the colour. …

Prof Javier Aizpurua, leader of the theoretical team from San Sebastian complains: “Trying to model so many electrons oscillating inside the gold just cannot be done with existing theories.” He has had to fuse classical and quantum views of the world to even predict the colour shifts seen in experiment.

The new insights from this work suggest ways to measure the world down to the scale of single atoms and molecules, and strategies to make useful tiny devices.

Something to think about the next time you kiss.

The quantum mechanics of photosynthesis

Thankfully, Jared Sagoff included a description of photosynthesis (I’ve long since forgotten the mechanics of the process) in his May 21, 2012 article, Scientists uncover a photosynthetic puzzle, on the US Dept. of Energy’s Argonne National Laboratory website. From Sagoff’s article, here’s the photosynthesis  description along with a description of the quantum effect the scientists observed,

While different species of plants, algae and bacteria have evolved a variety of different mechanisms to harvest light energy, they all share a feature known as a photosynthetic reaction center. Pigments and proteins found in the reaction center help organisms perform the initial stage of energy conversion.

These pigment molecules, or chromophores, are responsible for absorbing the energy carried by incoming light. After a photon hits the cell, it excites one of the electrons inside the chromophore. As they observed the initial step of the process, Argonne scientists saw something no one had observed before: a single photon appeared to excite different chromophores simultaneously.

Here’s a gorgeous image of a leaf provided with the article,

While different species of plants, algae and bacteria have evolved a variety of different mechanisms to harvest light energy, they all share a feature known as a photosynthetic reaction center. Pigments and proteins found in the reaction center help organisms perform the initial stage of energy conversion. These pigment molecules, or chromophores, are responsible for absorbing the energy carried by incoming light. After a photon hits the cell, it excites one of the electrons inside the chromophore. As they observed the initial step of the process, Argonne scientists saw something no one had observed before: a single photon appeared to excite different chromophores simultaneously. [downloaded from the Argonne National Liaboratory website)

I was aware that scientists are working at hard at duplicating photosynthesis but until reading this upcoming excerpt from Sagoff’s article, I had not appreciated the dimensions of the problem,

The result of the study could significantly influence efforts by chemists and nanoscientists to create artificial materials and devices that can imitate natural photosynthetic systems. Researchers still have a long way to go before they will be able to create devices that match the light harvesting efficiency of a plant.

One reason for this shortcoming, Tiede [Argonne biochemist David Tiede] explained, is that artificial photosynthesis experiments have not been able to replicate the molecular matrix that contains the chromophores. “The level that we are at with artificial photosynthesis is that we can make the pigments and stick them together, but we cannot duplicate any of the external environment,” he said.  “The next step is to build in this framework, and then these kinds of quantum effects may become more apparent.”

Because the moment when the quantum effect occurs is so short-lived – less than a trillionth of a second – scientists will have a hard time ascertaining biological and physical rationales for their existence in the first place. [emphasis mine] “It makes us wonder if they are really just there by accident, or if they are telling us something subtle and unique about these materials,” Tiede said. “Whatever the case, we’re getting at the fundamentals of the first step of energy conversion in photosynthesis.”

Thanks to Nanowerk for the May 24, 2012 news item which drew this article to my attention.

Quantum mechanics and the naked eye

Dual Wave/Particle Nature of Light Credit: Meeblax from Flickr

It’s a stunning image and it accompanies a fascinating story about a team at the University of Cambridge. The researchers built a chip that converts electrons to a quantum state where they emit light that’s visible to the naked eye. Here’s more from a Jan. 9, 2012 news item on Nanowerk,

Quantum mechanics normally shows its influence only for tiny particles at ultralow temperatures, but the team mixed electrons with light to synthesise supersized quantum particles the thickness of a human hair, that behave like superconductors.

Building microscopic cavities which tightly trap light into the vicinity of electrons within the chip, they produced new particles called ‘polaritons’ which weigh very little, encouraging them to roam widely.

The Jan. 8, 2012 news release on the University of Cambridge website notes this,

Dr Gab Christmann working with Professor Jeremy Baumberg and Dr Natalia Berloff of the University of Cambridge, together with a team in Crete, produced the special new samples needed which allow the polaritons to flow around at will without getting stuck.

According to Christmann: “These polaritons overwhelmingly prefer to march in step with each other, entangling themselves quantum mechanically.”

By moving the laser beams apart, Dr Christmann and his colleagues directly controlled the sloshing of the quantum liquid, forming a pendulum beating a million times faster than a human heart.

In the end, these scientists are trying to produce a generation of ultrasensitive gyroscopes that would measure gravity, magnetic field, and create quantum circuits based on an electrical battery developed from this discovery about electrons and polaritons.

It never occurred to me that quantum mechanics could be made visible and it seems I’m not the only one (from the University of Cambridge news release),

But as Christmann says: “Just to see and prod quantum mechanics working in front of your eyes is amazing.”

 

Environmental decoherence tackled by University of British Columbia and California researchers

The research team at the University of British Columbia (UBC) proved a theory for the prediction and control of environmental decoherence in a complex system (an important step on the way to quantum computing) while researchers performed experiments at the University of California Santa Barbara (UCSB) to prove the theory.  Here’s an explanation of decoherence and its impact on quantum computing from the July 20, 2011 UBC news release,

Quantum mechanics states that matter can be in more than one physical state at the same time – like a coin simultaneously showing heads and tails. In small objects like electrons, physicists have had success in observing and controlling these simultaneous states, called “state superpositions.”

Larger, more complex physical systems appear to be in one consistent physical state because they interact and “entangle” with other objects in their environment. This entanglement makes these complex objects “decay” into a single state – a process called decoherence.

Quantum computing’s potential to be exponentially faster and more powerful than any conventional computer technology depends on switches that are capable of state superposition – that is, being in the “on” and “off” positions at the same time. Until now, all efforts to achieve such superposition with many molecules at once were blocked by decoherence.

The UBC research team, headed by Phil Stamp, developed a theory for predicting and controlling environmental decoherence in the Iron-8 molecule, which is considered a large complex system.

Iron-8 molecule (image provided by UBC)

This next image represents one of two states of decoherence, i. e., the molecule ‘occupies’ only one of two superpositions, spin up or spin down,

 

Decoherence: occupying either the spin up or spin down position (image provided by UBC)

Here’s how the team at the UCSB proved the theory experimentally,

In their study, Takahashi [Professor Susumu Takahashi is now at the University of Southern California {USC}] and his colleagues investigated single crystals of molecular magnets. Because of their purity, molecular magnets eliminate the extrinsic decoherence, allowing researchers to calculate intrinsic decoherence precisely.

“For the first time, we’ve been able to predict and control all the environmental decoherence mechanisms in a very complex system – in this case a large magnetic molecule,” said Phil Stamp, University of British Columbia professor of physics and astronomy and director of the Pacific Institute of Theoretical Physics.

Using crystalline molecular magnets allowed researchers to build qubits out of an immense quantity of quantum particles rather than a single quantum object – the way most proto-quantum computers are built at the moment.

I did try to find definitions for extrinsic and intrinsic decoherence unfortunately the best I could find is the one provided by USC (from the news item on Nanowerk),

Decoherence in qubit systems falls into two general categories. One is an intrinsic decoherence caused by constituents in the qubit system, and the other is an extrinsic decoherence caused by imperfections of the system - impurities and defects, for example.

I have a conceptual framework of sorts for a ‘qubit system’, I just don’t understand what they mean by ‘system’. I performed an internet search and virtually all of the references I found to intrinsic and extrinsic decoherence cite this news release or, in a few cases, papers written by physicists for other physicists. If anyone could help clarify this question for me, I would much appreciate it.

Leaving extrinsic and intrinsic systems aside, the July 20, 2011 news item on Science Daily provides a little more detail about the experiment,

In the experiment, the California researchers prepared a crystalline array of Iron-8 molecules in a quantum superposition, where the net magnetization of each molecule was simultaneously oriented up and down. The decay of this superposition by decoherence was then observed in time — and the decay was spectacularly slow, behaving exactly as the UBC researchers predicted.

“Magnetic molecules now suddenly appear to have serious potential as candidates for quantum computing hardware,” said Susumu Takahashi, assistant professor of chemistry and physics at the University of Southern California.

Congratulations to all of the researchers involved.

ETA July 22, 2011: I changed the title to correct the grammar.

SFU scientists set their phasers on stun; quantum biology and University of Toronto Chemists; P.R. and science journalism

Neil Branda and his colleagues from Simon Fraser University’s (SFU) 4D Labs have demonstrated that animals can be ‘switched off ‘ with exposure to ultra violet light then ‘switched on’ when exposed to standard light. From the news item on Nanowerk,

In an advance with overtones of Star Trek phasers and other sci-fi ray guns, scientists in Canada are reporting development of an internal on-off “switch” that paralyzes animals when exposed to a beam of ultraviolet light. The animals stay paralyzed even when the light is turned off. When exposed to ordinary light, the animals become unparalyzed and wake up.

In more Canadian news, chemists at the University of Toronto have observed quantum mechanics at work with marine algae.  From the news item on Nanowerk,

“There’s been a lot of excitement and speculation that nature may be using quantum mechanical practices,” says chemistry professor Greg Scholes, lead author of a new study published this week in Nature. “Our latest experiments show that normally functioning biological systems have the capacity to use quantum mechanics in order to optimize a process as essential to their survival as photosynthesis.”

Special proteins called light-harvesting complexes are used in photosynthesis to capture sunlight and funnel its energy to nature’s solar cells – other proteins known as reaction centres. Scholes and his colleagues isolated light-harvesting complexes from two different species of marine algae and studied their function under natural temperature conditions using a sophisticated laser experiment known as two-dimensional electronic spectroscopy.

… It also raises some other potentially fascinating questions, such as, have these organisms developed quantum-mechanical strategies for light-harvesting to gain an evolutionary advantage? It suggests that algae knew about quantum mechanics nearly two billion years before humans,” says Scholes.

Is Scholes suggesting the algae are more advanced with science than humans? I find that thought intriguing and perhaps useful if one believes that human beings are remarkably arrogant creatures who can benefit from a little humility.

On a completely different front, I’ve been doing some more thinking about science journalism and science public relations (I did refer to some of it in my series on science communication in Canada on this blog in Sept/Oct 2009 ) after last week’s posting about a science journalism study in the UK. In fact, my thinking on these matters was reignited by a posting Ruth Seeley made on her No Spin PR blog about why she calls her business ‘no spin’ and why she prefers the term ‘framing’,

Implicit in the word spin is the idea that deception is involved, facts are being turned on their heads, and/or there’s so much fast talking going on the truth would be unrecognizable even if it were part of the mix. The ‘truth’ is, it’s as much of an insult to call a public relations practitioner a ’spin doctor’ as it is to call a woman a ‘chick.’ And it is a female-dominated profession, although not yet at the most senior levels.

Despite the cross-fertilization that occurs between journalists and PR practitioners (since writing well is the foundation skill for both professions), there is also the perception that journalists are those who ferret out the truth and present it objectively, while PR folks do their best to deflect, disguise, and distract from the truth. The notion of the muck-racking journalist being free of bias is laughable in the 21st Century. We wouldn’t have populist, right-wing, and left-wing media outlets if bias weren’t inherent in every medium, whether it’s the way the headline is written, the fact that the story is covered at all, or the selective presentation of facts. The notion that objectivity is in disrepute is, thankfully, permeating the zeitgeist – and not a moment too soon.

Whether you view the world through rose-coloured glasses or not, whether you think all politicians are dishonest or revere those who occupy the corridors of delegated power, whether you’re a MacHead or a PC fan, we all have filters we apply to information, and these filters affect our decision-making processes.

There is nothing illegal, immoral, or unethical about choosing a frame. You need to be aware that there’s more than one framing choice. You need to consider the fact that others won’t choose the same frame as you. Ultimately, though, you will have to either pick one or leave the picture unframed. Choosing a frame and developing a strategy for its presentation is the heart of public relations. As a practitioner, aligning yourself with clients whose framing aligns with your beliefs and values is the soul of a successful PR consultancy.

Perception has never been reality. It just appears to be. That, I suspect, is a natural consequence of the human condition.

I mention Ruth in particular because her consultancy seems to be largely focused on science public relations (she does projects for Andrew Maynard [2020 Science] and, as you can see in her post, she is involved with the twitter science community).  Her comments reminded me of a rather provocative posting on Techdirt in May 2009,

One of the most common complaints about the trouble facing newspapers today is the woeful cry “but who will do investigative journalism?” Of course, that’s silly. There are plenty of new entities springing up everyday online that do investigative journalism — and do it well.

Romenesko points us to a column by Tim Cavanaugh taking this concept one step further: suggesting that a subset of PR people may end up taking on the role of investigative journalists . Now, I’m sure plenty of journalists are cringing at the concept — and certainly, as someone who gets bombarded daily with idiotic story pitches that are spun to such ridiculous levels I can only laugh at them (as I hit delete), it makes me cringe a bit. But some of his points are worth thinking about.

I went on to check Tim Cavanaugh’s article and after a brief description of the current publishing crisis and its effect on investigative journalism,

Here’s one hypothesis. Numbers from the U.S. Bureau of Labor Statistics suggest that in the decade from 1998 through 2007, another field was outgrowing, and perhaps growing at the expense of, traditional journalism. The number of people working as “reporters and correspondents” declined slightly in that period, from 52,380 in 1998 to 51,620 in 2007. But the number of public relations specialists more than doubled, from 98,240 to 225,880. (Because job types and nomenclature change substantially, I have used only directly comparable jobs. The U.S. economy was still supporting 7,360 paste-up workers in 1998, for example, while in 2007 some 29,320 Americans were working under the already antique title “desktop publishers.”)

So are flacks the future, or even the present, of investigative journalism? This interpretation makes intuitive sense. Important data points by which we continue to live our lives— the number of jobs that were created or destroyed by NAFTA, the villainy of the Serbs in the Yugoslav breakup, all sorts of projected benefits or disasters in President Obama’s budget plans— are largely the inventions of P.R. workers.

And though it’s considered wise to believe the contrary, these communications types are not constructing all these news items entirely (or even mostly) by lying. Flackery requires putting together credible narratives from pools of verifiable data. This activity is not categorically different from journalism. Nor is the teaching value that flackery provides entirely different from that of journalism: Most of the content you hear senators and congressmen reading on C-SPAN is stuff flacks provided to staffers.

The debate itself is not all that new as the relationship between public relations and journalism is at least one century old. One of the earliest PR practitioners was a former journalist, Ivy Lee. As for borrowing from the social sciences (the term framing as used in Ruth’s posting is from the social sciences), that too can be traced backwards, in this case, to the 1920s and Edward Bernays who viewed public relations as having huge potential for social engineering.Towards the end of his life (1891 – 1995) he was quite disappointed, (according Stuart Ewen’s book, PR! A Social History of Spin) in how the field of public relations had evolved. Ewen (wikipedia entry) is highly critical of the profession as per this May 2000 interview with David Barsamian,

Part of why the history of PR is so interesting is because you see that it’s a history of a battle for what is reality and how people will see and understand reality. PR isn’t functioning in a vacuum. PR is usually functioning to try to protect itself against other ideas that are percolating within a society. So under no circumstances should what I’m saying about Bernays in terms of the use of social psychology indicate that these are automatic processes that always work. They don’t always work. They don’t always work because to some extent, despite what [Walter] Lippman said, people don’t just function by pictures in their heads. They also experience things from their own lives. Often their experiences are at odds with the propaganda that’s being pumped out there.

As you can see, for Ewen PR is synonymous with propaganda which, by the way, was the title for a book by Edward Bernays.

I’ve worked in public relations and in marketing and find that the monolithic claims made by folks such as Ewen have elements of truth but that much of the analysis is simplistic. That said, I think the criticism is important and quite well placed as there have been some egregious and deeply false claims made by PR practitioners on behalf of their clients. Still, it bothers me that everyone is contaminated by the same brush.  Getting back to Ruth’s post: In a sense, we are all PR professionals. All of us choose our frames and we constantly communicate them to each other.

Happy weekend.