Tag Archives: Ying Wang

Nanoscopic advance of colossal (!) significance by Danish quantum physicists

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it’s not often you see the word ‘colossal’ in a science news release but it seems these Danish researchers are very excited about their breakthrough. From a January 26, 2023 news item on Nanowerk,

In a new breakthrough, researchers at the University of Copenhagen, in collaboration with Ruhr University Bochum, have solved a problem that has caused quantum researchers headaches for years. The researchers can now control two quantum light sources rather than one. Trivial as it may seem to those uninitiated in quantum, this colossal breakthrough allows researchers to create a phenomenon known as quantum mechanical entanglement. This in turn, opens new doors for companies and others to exploit the technology commercially.

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A January 26, 2023 University of Copenhagen press release (also on EurekAlert), which originated the news item, provides context and more detail,

Going from one to two is a minor feat in most contexts. But in the world of quantum physics, doing so is crucial. For years, researchers around the world have strived to develop stable quantum light sources and achieve the phenomenon known as quantum mechanical entanglement – a phenomenon, with nearly sci-fi-like properties, where two light sources can affect each other instantly and potentially across large geographic distances. Entanglement is the very basis of quantum networks and central to the development of an efficient quantum computer.  

Today [January 26, 2023], researchers from the Niels Bohr Institute published a new result in the highly esteemed journal Science, in which they succeeded in doing just that. According to Professor Peter Lodahl, one of the researchers behind the result, it is a crucial step in the effort to take the development of quantum technology to the next level and to “quantize” society’s computers, encryption and the internet.

“We can now control two quantum light sources and connect them to each other. It might not sound like much, but it’s a major advancement and builds upon the past 20 years of work. By doing so, we’ve revealed the key to scaling up the technology, which is crucial for the most ground-breaking of quantum hardware applications,” says Professor Peter Lodahl, who has conducted research the area since 2001.  

The magic all happens in a so-called nanochip – which is not much larger than the diameter of a human hair – that the researchers also developed in recent years.

Quantum sources overtake the world’s most powerful computer 

Peter Lodahl’s group is working with a type of quantum technology that uses light particles, called photons, as micro transporters to move quantum information about.

While Lodahl’s group is a leader in this discipline of quantum physics, they have only been able to control one light source at a time until now. This is because light sources are extraordinarily sensitive to outside “noise”, making them very difficult to copy. In their new result, the research group succeeded in creating two identical quantum light sources rather than just one.

“Entanglement means that by controlling one light source, you immediately affect the other. This makes it possible to create a whole network of entangled quantum light sources, all of which interact with one another, and which you can get to perform quantum bit operations in the same way as bits in a regular computer, only much more powerfully,” explains postdoc Alexey Tiranov, the article’s lead author. 

This is because a quantum bit can be both a 1 and 0 at the same time, which results in processing power that is unattainable using today’s computer technology. According to Professor Lodahl, just 100 photons emitted from a single quantum light source will contain more information than the world’s largest supercomputer can process.

By using 20-30 entangled quantum light sources, there is the potential to build a universal error-corrected quantum computer – the ultimate “holy grail” for quantum technology, that large IT companies are now pumping many billions into.

Other actors will build upon the research

According to Lodahl, the biggest challenge has been to go from controlling one to two quantum light sources. Among other things, this has made it necessary for researchers to develop extremely quiet nanochips and have precise control over each light source.

With the new research breakthrough, the fundamental quantum physics research is now in place. Now it is time for other actors to take the researchers’ work and use it in their quests to deploy quantum physics in a range of technologies including computers, the internet and encryption.

“It is too expensive for a university to build a setup where we control 15-20 quantum light sources. So, now that we have contributed to understanding the fundamental quantum physics and taken the first step along the way, scaling up further is very much a technological task,” says Professor Lodahl.  

The research was conducted at the Danish National Research Foundation’s “Center of Excellence for Hybrid Quantum Networks (Hy-Q)” and is a collaboration between Ruhr University Bochum in Germany and the the University of Copenhagen’s Niels Bohr Institute.

Here’s a link to and a citation for this colossal research,

Collective super- and subradiant dynamics between distant optical quantum emitters by Alexey Tiranov, Vasiliki Angelopoulou, Cornelis Jacobus van Diepen, Björn Schrinski, Oliver August Dall’Alba Sandberg, Ying Wang, Leonardo Midolo, Sven Scholz, Andreas Dirk Wieck, Arne Ludwig, Anders Søndberg Sørensen, and Peter Lodahl. Science 26 Jan 2023 Vol 379, Issue 6630 pp. 389-393 DOI: 10.1126/science.ade9324

This paper is behind a paywall.

Carbon nanotubes burst forth (in a phallic manner) from the flames

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Is this or is this not a phallic image?

Caption: This is a carbon nanotube growth. Credit: ITbM, Nagoya University

Caption: This is a carbon nanotube growth.
Credit: ITbM, Nagoya University

I suppose you could also describe it as a finger. In any event, the research associated with this image concerns a newly observed similarity between carbon nanotube (CNT) growth and hydrocarbon combustion (fuel combustion), according to an April 1, 2014 news item on ScienceDaily,

Professor Stephan Irle of the Institute of Transformative Bio-Molecules (WPI-ITbM) at Nagoya University and co-workers at Kyoto University, Oak Ridge National Lab (ORNL), and Chinese research institutions have revealed through theoretical simulations that the molecular mechanism of carbon nanotube (CNT) growth and hydrocarbon combustion actually share many similarities. In studies using acetylene molecules (ethyne; C2H2, a molecule containing a triple bond between two carbon atoms) as feedstock, the ethynyl radical (C2H), a highly reactive molecular intermediate was found to play an important role in both processes forming CNTs and soot, which are two distinctively different structures. The study published online on January 24, 2014 in Carbon, is expected to lead to identification of new ways to control the growth of CNTs and to increase the understanding of fuel combustion processes.

A March 31, 2014 Institute of Transformative Bio-Molecules (ITbM), Nagoya University press release (also on EurekAlert but dated April 1, 2014), which originated the news item, provides some specifics about carbon nanotubes and about the research,

CNTs are molecules with a cylindrical nanostructure (nano = 10-9 m or 1 / 1,000,000,000 m [one billionth of a metre]). Arising from their unique physical and chemical properties, CNTs have found technological applications in the fields of electronics, optics and materials science. CNTs can be synthesized by a method called chemical vapor deposition, where hydrocarbon vapor molecules are deposited on transition metal catalysts under a flow of non-reactive gas at high temperatures. Current issues with this method are that the CNTs are usually produced as mixtures of nanotubes with various diameters and different sidewall structures. Theoretical simulations coordinated by Professor Irle have looked into the molecular mechanisms of CNT growth using acetylene molecules as feedstock (Figure 1). The outcome of their research provides insight into identifying new parameters that can be varied to improve the control over product distributions in the synthesis of CNTs.

High level theoretical calculations using quantum chemical molecular dynamics were performed to study the early stages of CNT growth from acetylene molecules on small iron (Fe38) clusters. Previous mechanistic studies have postulated complete breakdown of hydrocarbon source gases to atomic carbon before CNT growth. “Our simulations have shown that acetylene oligomerization and cross-linking reactions between hydrocarbon chains occur as major reaction pathways in CNT growth, along with decomposition to atomic carbon” says Professor Stephan Irle, who led the research, “this follows hydrogen-abstraction acetylene addition (HACA)-like mechanisms that are commonly observed in combustion processes” he continues.

Combustion processes are known to proceed by the hydrogen-abstraction acetylene addition (HACA)-like mechanism. Initiation of the mechanism begins with hydrogen atom abstraction from a precursor molecule followed by acetylene addition, and the repetitive cycle leads to formation of ring-structured polycylic aromatic carbons (PAHs). In this process, the highly reactive ethynyl radical (C2H) is continually being regenerated, extending the rings of PAHs and eventually forming soot. The same key reactive intermediate is observed in CNT growth and acts as an organocatalyst (a catalyst based on an organic molecule) facilitating hydrogen transfer reactions across growing hydrocarbon clusters. The simulations identify an intriguing bifurcation process by which hydrogen-rich hydrocarbon species enrich hydrogen content creating non-CNT byproducts, and hydrogen-deficient hydrocarbon species enrich carbon content leading to CNT growth … .

“We started this type of research from 2000, and long simulation time has been a great challenge to conduct full simulations across all participating molecules, due to the relatively high strength of the carbon-hydrogen bond. [emphasis mine] By establishing and using a fast method of calculation, we were able to successfully incorporate hydrogen in our calculations for the first time, which led to this new understanding revealing the similarity between CNT growth and hydrocarbon combustion processes. This finding is very intriguing in the sense that these processes were long considered to proceed by completely different mechanisms” elaborates Professor Irle.

I’m always impressed with the determination and persistence scientists demonstrate in their work and taking almost 14 years to study hydrocarbon combustion and carbon nanotube  growth in such detail is another among many, many such examples.

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

Quantum chemical simulations reveal acetylene-based growth mechanisms in the chemical vapor deposition synthesis of carbon nanotubes by Ying Wang, Xingfa Gao, Hu-Jun Qian, Yasuhito Ohta, Xiaona Wu, Gyula Eres, Keiji Morokuma, and Stephan Irle, Carbon 72, 22-37 (2014). DOI:10.1016/j.carbon.2014.01.020

This paper is behind a paywall.

Nanotechnology-enabled detection of landmines with the naked eye

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Researchers at the University of Connecticut have developed a device that makes the location of buried landmines and other hidden explosive devices visible to the naked eye. Colin Poitras in his May 4, 0212 posting on the University of Connecticut website provides some background information about landmines and their detection,

Each year, as many as 25,000 people are maimed or killed by landmines around the world, including large numbers of civilians.

While landmines are inexpensive to produce – about $3-$30 each, depending on the model – finding and clearing them can cost as much as $1,000 per mine. It is a slow and deliberative process. Specially trained dogs are the gold standard, but they can be distracted by larger mine fields and eventually tire. Metal detectors are good, but they are often too sensitive, causing lengthy and expensive delays for the removal of an object that may turn out to be merely a buried tin can.

A UConn chemical engineering doctoral student hopes to help. Ying Wang, working in conjunction with her advisor, associate professor Yu Lei, has developed a prototype portable sensing system that can be used to detect hidden explosives like landmines accurately, efficiently, and at little cost.

The Aug. 2, 2012 news item on Nanowerk provides some information about the device ,

A chemical sensing system developed by engineers at the University of Connecticut is believed to be the first of its kind capable of detecting vapors from buried landmines and other explosive devices with the naked eye rather than advanced scientific instrumentation.

The research was first reported in the May 11, 2012 online edition of Advanced Functional Materials.

The key to the system is a fluorescent nanofiberous film that can detect ultra-trace levels of explosive vapors and buried explosives when applied to an area where explosives are suspected. A chemical reaction marking the location of the explosive device occurs when the film is exposed to handheld ultraviolet light.

Detection of buried explosives. (Image courtesy of Ying Wang) Downloaded from the University of Connecticut website: http://today.uconn.edu/blog/2012/05/improving-the-detection-of-landmines/

The Aug. 2, 2012 news item on e! Science News provides additional detail about this detection system,

The system can detect nitroaromatics such as those found in TNT and 2,4-DNT (the military’s primary explosive and the principle components in landmines) as well as the elements used in harder to detect plastic explosives such as HMX, RDX, Tetryl, and PETN. The ultra-sensitive system can detect elements at levels as low as 10 parts per billion (TNT), 74 parts per trillion (Tetryl), 5 ppt (RDX), 7 ppt (PETN) and 0.1 ppt (HMX) released from one billionth of a gram of explosive residue.

If there is no explosive vapor present, the recyclable film retains a bright fluorescent cyan blue color when exposed to ultraviolet light. If explosive molecules are present, the fluorescence is quenched and a dark circle identifying the threat forms on the film within minutes.

“Our initial results have been very promising,” says UConn Dr. Ying Wang, who developed the system as a chemical engineering doctoral student working under the supervision of UConn Associate Engineering Professor Yu Lei. “We are now in the process of arranging a large-scale field test in Sweden.”

Rather than using sophisticated chemical modifications or costly synthetic polymers in preparing the sensing material, UConn scientists prepared their ultra-thin film by simply electrospinning pyrene with polystyrene in the presence of an organic salt (tetrabutylammonium hexafluorophosphate or TBAH). This resulted in a highly porous nanofiberous membrane that absorbs explosive vapors at ultra-trace levels quickly and reliably. The film also has excellent sensitivity against common interferences such as ammonium nitrate and inorganic nitrates. Initial vapor detection took place within seconds with more than 90 percent fluorescent quenching efficiency within six minutes.

Poitras’ posting notes the researchers have teamed with a landmine removal company (Note: I have removed some links),

One of the world’s top private landmine clearing companies, located in South Sudan, is currently working with Lei and Wang in arranging a large-scale field test. The results of the field test could be of interest to the United Nations, which has worked to make war zones plagued by old landmines safer through its United Nations Mine Action Service. It is estimated that there are about 110 million active landmines lurking underground in 64 countries across the globe. The mines not only threaten people’s lives, they can paralyze communities by limiting the use of land for farming and roads for trade.
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“When I started working with landmines, I was thrilled,” says Wang, who received her bachelor’s degree in chemical engineering from Xiamen University in China in 2004 and her master’s degree in biochemical engineering from Xiamen University in 2007. “I knew this would be a really good application of our work. It can save lives.”

Wang and Lei are currently working with UConn’s Center for Science and Technology Commercialization (CSTC) in obtaining a U.S. patent for their explosive detection systems.

I last wrote about landmine detection systems in an Aug. 22, 2011 posting which centered on an ‘ultra’ portable system.

There are a number of ‘landmine’ programmes, I found these two: United Nations Mine Action Service, aka, E-MINE: Electronic Mine Information Network and the United Nations Association of the United States of America Adopt-A-Minefield Program.