This is a guest post and part of our ongoing Student Life series

Kilian Liss, School of Physics

Arriving in China

Before going to FPISC in Hefei which started on Sunday the 1st of July, I decided to spend a few days of sightseeing in Shanghai. It is the largest city in China, with a population of more than 24 million, about the same as that of Australia. As a result, the city is incredibly dense with modern skyscrapers everywhere. A strong history may be found in areas such as the bund, where buildings built by international settlers remain, meanwhile beautiful traditional Chinese walking streets may be found in places such as the Yu Gardens.

I arrived at Pudon International Airport on the 28th of June, 0:05 am, and the first thing I did was take a cab to a hotel nearby, and slept. The morning after I made my way to the city center, where I stayed until the 1st of July. In China, WeChat is not only the dominant messaging app, but it is also used to make payments for absolutely anything from flights, to grocery items, to bike sharing systems, and anything in between. It is also commonly used for business applications, and was the main form of communication with the event organizers of FPISC. Since this was my second time in China, I had already everything set up, including bank account and WeChat pay, making travel in China much simpler in terms of finance. The subway system in here was also very similar to the system in Guangzhou that I was already familiar with, cabs and buses also ran in a similar way.

Shanghai is by far the most international city in China that I have visited so far. Not only is the Bund scattered by European styled building left behind by settlers, but laws are also well enforced here and the city is clean. Meanwhile in other Chinese cities that I have been to such as Shantou, you can appreciate why China is still considered a developing country.

This is partly what I love about China, it is so diverse and culture varies significantly depending on which city you are visiting. While the Chinese tend to not have much political freedom, I feel that they have far more economic freedom than western counterparts. New businesses don’t have much regulations to struggle through, but instead have to keep a good reputation in order to build trust within its customer base. Many westerners criticize the control that the government have here on its people, however I believe it leads to the preservation of a beautiful and unique culture that I have not seen anywhere else in the world before. People have a strong sense of family connection, which seems to be a result of Confucius philosophy.

USTC – Hefei

The University of Science and Technology of China (USTC) in Hefei, is said to be one of the best universities in china in terms of research in physics, and after visiting there for 2 weeks, it became clear to me why. They focus a lot in quantum mechanics, fusion energy, nano-technology and Astrophysics, giving them a leading edge in revolutionary research.

During their summer break (Australian Winter), they organized 3 international summer camps running in parallel. One of them being the Future Physicist International Summer Camp (FPISC), which I participated in, and the other two were focused on Chemistry/Biology and Artificial Intelligence. We all shared the same hotel, opening ceremony, and farewell party, but aside from that each summer camp had there own set of classes.

USTC gave us a lot of freedom during the period of our stay. We were expected to attend lectures and activities as prescribed to us by timetable, however outside of those scheduled class times we were free to do what we wanted. In afternoons, we’d explore the city together in small groups, and since I already had experience with how the Chinese transportation system works, I often helped people out navigating public transport. The taxis were relatively cheap, and a good back up plan for getting back to our hotel, however when possible we still tried to catch the bus as it was even cheaper.

The first week of FPISC was mainly composed of lectures, cultural activities and lab tours. Each lecture was held by a separate professor, where they would introduce to us a field of ongoing research that they were involved in. Most students understood the general idea of the lectures, however many topics could easily have required a whole semester worth of study in order to fully comprehend. Nonetheless, it was really eye opening in terms of how broad and complex research really is.

The cultural activities were aimed at introducing us to Chinese culture, where they would introduce activities to us such as calligraphy, Kong fu or Tea Culture. At one point, a group of USTC students performed for us using traditional Chinese instruments, and afterwards they let us have a try for ourselves.

The lab tours gave us a glimpse of what life as a researcher is like. They took us into a lab where superconducting nano-technology was being developed, and another were research on plasma fusion technology was being conducted. USTC has also sent various satellites to space, including the Dark Matter Explorer and another which achieved quantum tunneling from earth to space.

The second week was mainly focused on lab work, were we got to work with a professor of our choice based on the lectures given in week 1. I chose to work with professor Wenzhe Mao who focuses on research in plasma fusion devices, and works in the facility containing the Keta Torus eXperiments (KTX). Along with lab work, we also had cultural activities, excursions to Hefei Institutes of Physical Sciences, Anhui Museum, iFlytek’s headquarters and a farewell party towards the end.

For me personally, the absolute highlight of this trip in china was our weekend in Huangshan (Yellow Mountain). It is by far the most impressive natural rock formations that I have ever seen, and it truly felt like we walked into a science fiction fantasy movie. Since we had the weekend off, a few friends and I got into a group together and organized the trip. We left by train on Friday afternoon, spent the first night at the bottom of the mountain, and the second at the top. On the second night we got up at 3:30 in the morning and made our way to watch the sunrise. It was cold and dark, however after seeing yellow clouds emerging far from distance within the mountains, it was all worth it. The area was completely surrounded by cliffs, and while the footpaths were fairly well built, one should still be sure they are not afraid of heights before attempting some of these walks. We worked together as a team to get the trip going, and since there was only 1 native Chinese speaker within the 12 of us, I took charge for organizing train tickets using the Mandarin Chinese that I had learned in class at UOW.

Lectures

Lectures were mainly held during week 1 of FPISC, and went on for about an hour each. They talked about various fields of research ongoing within USTC, some of which was performed on campus, while others was done in collaboration with other institutes or industries. Below is a general outline of the content involved within the lecture based on what I understood. Please keep in mind that some content within lectures could have taken a whole semester or more to fully comprehend, and my summaries written bellow may not be completely accurate. They are listed in the same order that the lectures were presented to us.

  • Bacterial Motile Behavior – Junhua Yuan – Junhua’s research is in Biological Physics, and studies how Ecoli bacteria propagate. Studying the ecoli’s Flagella based movement could help understand how proteins within any living organism move. Once this mechanism is fully understood, it could potentially be used in transport methods for medicines.
  • Quantum Memory – Dong Shengding – Here they make use of entangled photons to store quantum information in the form of qubits for the use in quantum computing. Polarization filters are used to polarize the spin angular momentum of the entangled photons, which can then be used to store the density matrices of the quantum information. Meanwhile hologram grating is used to prepare the orbital angular momentum of the photons. In total, 7 properties of the photons go into entanglement.
  • Radio Krypton Dating with Atom Trap Trace Analysis – Wei Jiang – Krypton dating is used to date some of the oldest water samples in the world, which gives insights about global ground water cycles. This has various applications, such as determining whether water reservoirs in dry remote places such as the Sahara desert or the Australian outback are renewable or not. Other uses of Krypton water dating are in the study of the earths climate and weather patterns around 1 millions years ago using samples obtained from ice in Antarctica. Atom traps using lasers are used to trap 81Kr36+ and 81Kr35+ isotopes, making it easier to count the number of atoms within a given sample. Figure 3 is a picture of the experimental set up of the atom trap.
  • Dark Mater Particle Explorer (DAMPE) – Yunlong Zhang – USTC is involved with multiple approaches in trying to solve the dark mater problem in Astrophysics. Some include developing alternative theories for gravity, producing dark mater using the Large Hadron Collider, building detectors deep underground, and sending satellites with various detectors into space.
  • Correlated Oxide Nano-Electronics – Guanglei Cheng – Silicon transistor based nano-chips are approaching their physical limits related to speed and size, so alternative methods for computation are being investigated. Currently, there are two promising technologies, these are correlated oxides, which are superconducting nano-electronics, or spintronics, which is also known as quantum computing. USTC is exploring the possibility of combining these two fields. A lab is currently being developed on campus, which already has instruments capable of writing and erasing nanowires of 2 nm thickness. A superconducting waveguide for electrons has been developed, and together with the use of majonara particles, the waveguide is capable of preserving coherence within quantum computations.
  • Colloidal Quantum Dot Lasers – Fengjia Fan – Fengjia is working on making wavelength tunable lasers commercially viable. In order to do this, a large spherically shaped molecule, called a quantum dot, is is dissolved into a liquid solution. Changing the concentration of various solvents can adjust the wavelength of laser emitted by the quantum dots. Current challenges involve lowering the threshold energy of the laser, and one solutions is to apply a uniform biaxial strain using chemical coating around the quantum dot. This widens the electrons energy bands, thus the electrons are free to move into a lower energy state.
  • Galaxies in Numerical Simulations – Xufen Wu – Numerical Simulations are used to test various theories on the formation of the universe. Alternative theories about gravity are being investigated to solve the dark matter issue, and comparing simulated variables such as velocity to measured variables can be used to test the validity of the alternative theories.
  • Plasma Physics – Wenzhe Mao – The world’s energy consumption is increasing, and our current energy resources are problematic, therefore alternatives are required. One such alternative is nuclear fusion from Hydrogen to Helium (not to be confused with fission). This would provide safe nuclear energy with no hazardous radioactive wastes. While fusion reactions occur regularly on the sun, and have been achieved in labs, no one has yet managed to build a device that harnesses energy from this process. Multiple facilities worldwide exist in investigating fusion energy, and these include Stellarators, Tokamaks, and Reverse Field Pinch. They all confine plasma within a torus shaped vacuum chamber, and with enough pressure, temperature and confinement time, plasma fusion should occur. There are currently two fusion devices in Hefei city, a Tokamak at Hefei Institutes of Physical Sciences, and a reverse field pinch at USTC. My lab work was based on this topic, and more information is provided in section 3.
  • Search for 0vDBD Events at Deep Underground Laboratory – Changqing Feng – It is currently unknown whether Neutrino behave with a Dirac or Majonara nature, and a detection of Zero Neutrino Double Beta Decay (0vDBD) would confirm the latter. Current theory predicts that 0vDBD would have a half life of over 1025 years, which makes it extremely difficult to detect, so long measurements, ultra low background radiation and a large sample size is required. A 2400 m underground lab has been built inside a mountain to accommodate for the low radiation background, and 100 kg of >136Xe isotopes are being used. The project is currently being led by Tsinghua University in collaboration with many others.
  • Next Generation Nanolithography Methods after 193i – Wang Liang – Lithography is the current industrial method used for mass production of silicon chips such as CPUs and others. Light of short wavelength is shone through a mask, which then burns a circuit into the chip. Currently lenses are being used to reduce the size of the image, although USTC is looking into using a bow tie antenna to focus the light.

Set up of the atom trap used in Krypton Carbon Dating.

Cultural Activities

As a way of introducing Chinese culture to us, USTC provided us with occasional cultural activities throughout the summer camp. Each activity was based on a separate topic and most of them had us engaged within the activity. Activities that we participated in included Marshall Arts, Calligraphy, Musical Instruments, Tea Culture and some history on the Chinese language.

Lab Tours

Meanwhile during the Lab tours, we got to see:

  • Muon Detection Instruments – Some of which they have sent to space on a Satellite called the Dark Matter Explorer
  • A Krypton Atom Trap – Used for water dating, water samples have come from places such as the Sahara desert, Antarctica and the Australian Outback
  • Photon Quantum Entanglement Memory Cell – Which is the first proof of concept in the world for storing quantum information in the form of Qubits using entangled photons.
  • The Keta Torus eXperiment (KTX) – A Reverse Field Pinch (RFP) device used for research in Plasma Fusion Energy
  • Correlated Oxide Nano-electronics – Where they produce superconducting nano-electronics. Here they also managed to make superconducting waveguides for electrons, which is can be used for preserving coherence within Quantum Computing

Lab Work

The KTX

The goal of magnetic plasma fusion devices is to harness energy by use of nuclear fusion from Hydrogen to Helium. Nuclear fusion occurs regularly in the sun, and while it has been achieved in labs on earth, no one has yet managed make a net gain of energy from it. If this goal were to be achieved, it would provide the world with an ideal energy alternative that would be safe to manufacture, and with no significantly hazardous wastes. This technology is therefore of high interest within the goal of world wide sustainable energy.

There are currently 3 main types of magnetic fusion devices, these are Stellarators, Tokamaks, and Reverse Field Pinch (RFP). They all follow the same basic principle of confining plasma within a torus (donut) shaped vacuum chamber, and if sufficient pressure, temperature and confinement time is applied to the plasma, nuclear fusion should occur. Tokamaks primarily use exterior magnetic fields to achieve plasma pressure, while RFPs make use of a high plasma current flowing through the torus. The flowing current generates its own magnetic field in such a way that the plasma squeezes upon itself. Stellarators make use of a twisting path that the plasma current flows through, designed to cancel out any instabilities within the plasma.

Keta Torus eXperiments (KTX)

During the second week of the summer camp, I chose to do my lab work with Wenzhe Mao, based on the Plasma Physics lecture. We additionally got to chose whether we wished to work the Keta Torus eXperiments (KTX), or work on the theory/data analysis, and of course, I chose to work with the KTX. KTX is the RFP that USTC has on campus, meanwhile Hefei Institutes of Physical Sciences has the worlds first fully superconducting Tokamak named the Experimental Advanced Superconducting Tokamak (EAST), and surprise surprise, it’s located in the east part of the city. In total we spent about 3 days in the KTX facility, and 1 day on a field trip to EAST. The first day was focused on understanding how KTX works, on the second we learnt how to operate the KTX, and on the third we ran some experiments using the KTX.

A schematic diagram of the Stellarator, Tokamak and Reversed Field Pinch (RFP) Taken from source [1]

While EAST was built for more in depth research, KTX was built by USTC mainly for educational purposes. KTX can currently achieve a plasma current of 100 ms, using a current of 100 kA. During the short blast, the plasma temperature inside KTX gets up to 10 million degrees hot and Currently USTC aims at increasing the power supply to 1 MA, which should in turn increase the plasma confinement time.

Tokamaks currently have achieved higher confinement time and plasma pressure when compared to RFPs, however a significant drawback of Tokamaks is that they unpredictably undergo disruptions. When this occurs, a large chunk of the plasma’s energy suddenly gets released back into the surrounding magnetic field, thus damaging the equipment. The cause of disruptions is currently unknown, but is an ongoing field of research and Machine learning algorithms are used for the prediction of disruption events. Since RFPs do not exhibit the issue of disruptions, they show to be more promising for industrial purposes, however more work is required to achieve the same level of confinement time and pressure as Tokamaks do.

The safety factor of a fusion device is a measure of how likely disruptions are to occur. While disruptions do not occur within RFTs, they can still be used to make measurenments of the safety factor. It can be calculate as follows:

where Bt is the toroidal magnetic field, Bp is the poloidal magnetic field, R is the major radius of the toroid and r is the location of the probe based on the minor radius of the toroid. Figure 6 illustrates the toroidal and poloidal
magnetic field components as required by the determination of q. During our third day in the facility, we fired the KTX multiple times in order to make to calculate the safety factor as a function of minor radius r. For each shot of the KTX, it took about 2 minutes for the capacitors that were used as power supply to charge.

A diagram that distinguishes the toroidal (blue) magnetic field to the
poloidal (red) magnetic field. Taken from source [2]

The shot would then last for about 100 ms, and multiple probes that were built into the machine would record their data onto the servers within the KTX facility. The data could only be accessed using the Wifi within the facility, and could be extracted using pre-written Matlab code. Further using Matlab, we wrote a script that took the value of the toroidal and poloidal magnetic field during the time of maximum plasma current, however since I was the only student in our team familiar with Matlab, we did not manage to finish in time.

Conclusion

Since I have family who are currently living in China, I decided to visit them during my remaining time after the summer camp. I spent about a week in Shantou, Guangdong province, and reunited with many other people who I met during the last time I was there.

Overall, FPISC was an amazing experience that really opened my eyes in terms of what’s happening in research within physics and how other cultures approach it. The trip made me realize how international research really is, as every major project seems to done under collaboration with various nations. I am very grateful to USTC for providing us with the opportunity to visit their campus, and UOW for getting me in touch with USTC and helping me out with financial matters.

I believe that next year UOW will be sending 5 students over to FPISC, and I truly encourage anyone who is studying physics to apply. Some advice that I have for future attendees, is to set up a bank account, since the entirety of the 8000 RMB travel allowance is handed out in the form of cash and other students of FPISC felt uncomfortable carrying around such a large sum of money. It also allows you to use WeChat pay, which is the dominant form of transaction in China, and makes it much easier to book hotels, train tickets or any other bookings that may need to be made. I personally went with the China Construction Bank (CCB), setting up the account only took about 40 minutes at a local branch, and they help you out connecting your account to WeChat.

References

[1] Tutorial on Keda Torus eXperiment reversed field pinch Tao Lan, on behalf of KTX Team, School of Physical Sciences, University of Science and Technology of China, Hefei, China – Given to us by professor

[2] Toroidal and poloidal By Dave Burke 2006