Nav: Home

Cooling nanotube resonators with electrons

October 08, 2019

Mechanical resonators have been used with great success as new resources in quantum technology. Carbon nanotube mechanical resonators have shown to be excellent ultra-high sensitive devices for the study of new physical phenomena at the nanoscale (e.g. spin physics, quantum electron transport, surface science, and light-matter interaction).

Mechanical resonators are often used to observe and manipulate the quantum states of the motion of relatively large systems. However, the drawback lies in the thermal noise force, which, if not controlled properly, ends up diluting any possibility of observing the quantum effects. Thus, scientists have been seeking for effective methods to cool down these systems down to the quantum regime and be able to observe quantum effects on demand. One of these approaches has been to use the transport of electrons along the resonator to cool down the system.

Many theoretical schemes have been proposed to cool these mechanical resonators using different electron transport regimes, but experimental difficulties have made it extremely challenging in terms of device fabrication and measurement. Despite many efforts, only one experimental realization of cooling was reported over a decade ago, in which researchers were able to cool down the system to a population number of 200 quanta, which is far from the quantum regime.

Now, in a new study published in Nature Physics, ICFO researchers Carles Urgell, Wei Yang, Sergio Lucio de Bonis, and Chandan Samanta, led by ICFO Prof. Adrian Bachtold, in collaboration with researchers from ICN2 in Barcelona and CNRS in France, have been able to demonstrate an experiment in which they cool down a nanomechanical resonator to 4.6 +- 2.0 quanta of vibration.

In their study, the team fabricated the resonator by growing a carbon nanotube between two electrodes, where in the last step of the fabrication process, they employed a chemical vapor deposition method to minimize any possible residual contaminant on the device. Then they inserted the system in a dilution refrigerator and cooled it down to 70 mK. The novelty of their technique lied in applying a constant current of electrons through the resonator. When a constant current was applied to the resonator, the electrostatic force of the electrons impacts the dynamics of the vibrations. These modified vibrations react back on the electrons, making a closed loop with a finite delay. This back-action of the electrons on the vibrations can be used to amplify or reduce the thermal vibration fluctuations. In the latter case, they used it to cool down the system to reduce the thermal displacement fluctuations, allowing them to approach the quantum regime limit mentioned before, with a population number never reached before when compared to previous work.

The results of the study have confirmed this method to be an excellent and very simple way to cool down nanomechanical resonators, which could be of utmost importance to scientists working in nanomechanics and quantum electron transport since it will become a powerful resource for quantum manipulation of mechanical resonators.

Link to the paper:

Link to the research group led by ICFO Prof. Adrian Bachtold:

ICFO-The Institute of Photonic Sciences

Related Electrons Articles:

Hot electrons harvested without tricks
Semiconductors convert energy from photons into an electron current. However, some photons carry too much energy for the material to absorb.
Cooling nanotube resonators with electrons
In a study in Nature Physics, ICFO researchers report on a technique that uses electron transport to cool a nanomechanical resonator near the quantum regime.
New method for detecting quantum states of electrons
Researchers in the Quantum Dynamics Unit at the Okinawa Institute of Science and Technology Graduate University (OIST) devised a new method -- called image charge detection -- to detect electrons' transitions to quantum states.
Slow electrons to combat cancer
Slow electons can be used to destroy cancer cells - but how exactly this happens has not been well understood.
How light steers electrons in metals
Researchers in the Department of Physics of ETH Zurich have measured how electrons in so-called transition metals get redistributed within a fraction of an optical oscillation cycle.
Twisting whirlpools of electrons
Using a novel approach, EPFL physicists have been able to create ultrafast electron vortex beams, with significant implications for fundamental physics, quantum computing, future data-storage and even certain medical treatments.
Inner electrons behave differently in aromatic hydrocarbons
In an international research collaboration between Tsinghua University in Beijing and Sorbonne University in Paris, scientists found that four hydrocarbon molecules, known for their internal ring structure, have a lower threshold for the release of excess energy than molecules without a similar ring structure, because one of their electrons decays from a higher to a lower energy level, a phenomenon called the Auger effect.
Exotic spiraling electrons discovered by physicists
Rutgers and other physicists have discovered an exotic form of electrons that spin like planets and could lead to advances in lighting, solar cells, lasers and electronic displays.
Racing electrons under control
The advantage is that electromagnetic light waves oscillate at petaherz frequency.
Electrons go with the flow
You turn on a switch and the light switches on because electricity 'flows'.
More Electrons News and Electrons Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at