Metal droplets can also be “chased on the track”

In life, many people become two stars of the “CP (pairing) powder.” But you know what – our scientists in the lab, found that liquid metal droplets can actually lock “CP”, in orbit chase. This is the first time that scientists have discovered the co-movement behavior of droplets caused by the phenomenon of wave particle dilike in the macro system of liquid metals, and it has implications for the exploration of the understanding of electron spin behavior at the atomic level and even planetary motion at the cosmic scale.

Raindrops fall on the surface of the water, sloshing around – an unusual phenomenon of disintegration that fascinates physicists. (File picture)

The in-track rotation chase motion (top view) observed in the experiment of the metal droplet pair. The left and right figures show a short-range self-locking droplet pair and a long-range self-locking droplet pair (arrowindicates the direction of droplet motion). (File picture)

Recently, Professor Liu Jing’ research team from Tsinghua University and the Institute of Science and Technology of the Chinese Academy of Sciences, published a paper in the Journal of the American Physical Society, Physical Review Fluids, revealing the macro-particle dilike of the liquid metal navigation wave system, which occurs in the liquid metal oscillation liquid pool triggered by the navigation wave, the quantum orbit phenomenon and the metal drop chase effect.

This is the first time that scientists have discovered the co-movement behavior of droplets caused by the phenomenon of wave particle dipicness in the macro system of liquid metals. Liu Jing, professor of biomedical engineering at Tsinghua University School of Medicine and a double researcher at the Institute of Science and Technology of the Chinese Academy of Sciences, told the Economic Daily: “In particular, the metal drop-in-orbit chase behavior is very interesting and vivid, and there is some inspiration for the exploration of the understanding of the electron spin behavior at the atomic level and even the planetary motion of the cosmic scale.” “

Everything waves, how to see

What is a navigation wave? This is a concept in quantum mechanics.

In 1924, the French scientist De Brouy first put forward the bold hypothesis of “all waves”, that, like light, all matter has the appearance of particles. Wave particle dilike is the cornerstone of the development of quantum mechanics. Based on this, DeBroe proposed the navigation wave theory to describe the motion of the quantum world. According to this theory, quantum particles, such as electrons, are guided by a navigational wave field. A few years later, physicists found a macro system that bears a striking resemblance to DeBroe’s theory of navigational waves, the fluid navigation wave system.

In classical fluid mechanics, a droplet placed on a vibrating surface in a vertical direction can continue to bounce on the surface without fusion. Further, this type of non-fusion droplet is subject to the local wave action of the impact surface of its impact surface and produces a guiding horizontal motion. This droplet motion bears striking resemblance to the quantum particle motion described in the theory of navigational waves in quantum mechanics.

In this regard, we can recall the rainy day. At that time, have you ever seen raindrops stir up fleeting ripples on the puddles? Some droplets that hit the water do not immediately fuse with the water, but remain on the surface for a while.

This anomalous disintegration and the wealth of kinetic knowledge behind it once fascinated physicists. The study found that the non-fusion effect is caused by the collision between the droplet and the surface of the fluid separated by another layer of media, such as air. The presence of non-fusion also allows scientists to “suspend” droplets from liquid surfaces – the secret to suspension is to let both the surface and the droplets move.

Dr. Tang Jianbo, the first author of the paper, said that in the study, the classic Faraday experiment was commonly used, that is, to allow a liquid pool to be controlled in the vertical direction of controlled vibration. As a result, droplets placed on the surface of the pool vibrate with the surface of the liquid, periodically bouncing, which in turn prevents the two from merging. In such a droplet-pool system, each time a bouncing droplet hits a vibrating pool, it leaves a local wave field with the droplet as the center and diffuses outwards on the surface of the pool. The droplets and the ripples they produce on the liquid surface constitute a macro-wave particle-like system.

Droplets that jump in the vertical direction obtain the thrust in the horizontal direction by interacting with its local navigation wave to generate displacement. This droplet’s self-boosting state and motion pattern are compared to the image as “walking”. Walking droplets bear many similarities with the quantum world particles described in the theory of navigational waves in quantum mechanics.

Previous studies have shown that the suspended droplets in this fluid navigation wave system can simulate a series of mysterious behaviors in the quantum field, such as tunneling, interference and so on. The understanding of the second image of wave grain at the macro level makes the study of fluid navigation wave arouse the attention of the scientific community in recent years.

Droplet CP, How to Dance

Why is it so important? Because other research approaches are too difficult: in addition to quantum systems, there is a common wave of particle motion in physical systems, which often occurs either on extreme scales or with special conditions, which makes direct observation and control difficult. For the macro fluid navigation wave system, its driving parameters and system structure can be flexible and easy to realize.

Previously, studies have examined the dynamic behavior of individual or multiple droplets in a conventional fluid navigation wave system, but they all have drawbacks: some are confined to single droplets, single navigation wave fields, and some have overcomplicated the structure of the system – so scientists are looking for a new pattern of droplet motion. Now, Chinese scientists have done it.

What happens when a fluid navigation wave system encounters a liquid metal called a Terminator fluid? That’s exactly what Chinese researchers want to explore.

Compared to conventional fluids used in conventional fluids used in classical fluid navigation wave systems, such as silicone oils, the room temperature liquid metal tantalum alloy has unique fluid characteristics, such as great density and surface tension, and extremely low viscosity. In response, the research team designed a liquid metal navigation wave system to study its macro-wave particle duality.

“Differences in fluid properties do lead to different experimental results. However, the initial observation was a bit disappointing – we were unable to reproduce the ‘walking’ state of the droplets in a liquid metal system. Previous studies have shown that ‘walking’ of droplets is a prerequisite for stimulating droplet stoic horizontal movement and other more complex behaviors. Dr Tang Jianbo, the first author of the work, said: “However, the moment we tried to add a second drop to the liquid metal system, we immediately became excited. “

It turns out that while a single liquid metal droplet remains stationary horizontally, when two droplets of different sizes meet on the pool, they automatically couple (self-locking) into a droplet pair and then rotate in the pool.

The researchers also found that the synergy of droplets in liquid metal systems exhibits a series of very novel features: first, these pairs always rotate precisely along concentric rings with the center of the pool as the center. Secondly, the droplets have the direction to do rotational motion. The coordinated movement of the droplets can be either the large droplets of the two chasing the small droplet rotation, or the small droplets chasing the large droplet rotation. The direction of the chase depends on the self-locking mode between the two droplets.

If the two droplets are adjacent to each other, the droplet pair takes the former rotation mode, and if the droplets are far away from each other, the droplet pair takes the latter rotation mode and the chasing direction is reversed. More interestingly, the rotation and chasing motion of the liquid metal droplet pair has different orbital radii and different self-locking distances, both of which have clear quantum numerical characteristics.

“Seeing these lively metal droplets chasing and orbiting on the surface of a pool of glittering metal gloss reminds me of the movement of micronuclear electrons around the nucleus and to the vast expanse of cosmic celestial bodies. Zhao Wei, a doctoral student who co-authored the work, said.

Behind the wheel, who should be

Behind these fascinating phenomena is a series of subtle interactions between droplets and the navigationwave fields on the surface of the pool.

The study found that in all liquid metal droplet pairs, small droplets always “arrive” before the large droplets coupled with them in the bounce. And it is precisely because of this vertical direction of the inconsistency of the bounce, causing the horizontal direction of the droplet movement.

“No such diversity of droplet quantum, orbital, directional droplet motion has ever been observed in previous systems, and we believe that the appearance of these droplets is due to the unique fluid properties of liquid metals. Professor Liu Jing, who led the study, said: “We have designed a series of experiments to reveal the underlying principles and mechanisms. “

The team studied the dynamic behavior of liquid metal pools and droplets. They found that this particular pattern of motion stems from the interaction between the droplet and the surface wave of the pool.

“However, unlike previous systems that had only a single navigation wave field, our current system produces a second global navigation wave field due to the abnormal surface tension of the liquid metal itself. Liu Jing explained: “In addition, in our system, droplets are horizontally thrusted by interacting with the local navigation wave field of the droplets coupled with them. “

The researchers also proposed a particle-navigation wave association framework for the composite navigation wave field, which could explain the observed experimental phenomena. They believe that the exploration of the liquid metal navigation wave system, on the one hand, enriches the research scope and knowledge of fluid dynamics instability, on the other hand, also greatly expands the meaning of the fluid dynamics layer wave particle dimetallicity.

“For example, we found that liquid metal droplets’ in-orbit chase motion in a dual navigation wave field is strikingly similar to the motion patterns of nanoparticle pairs in optical systems. “This means that we are likely to find similar movements in more physical systems, or to use uniform theories to understand the motion of different physical systems, ” Tang said. “

“We also see the possibility that the motion of other systems can be simulated by simply vibrating a liquid metal pool. I believe that there are certainly many scientific problems worth exploring in the liquid metal navigation wave system. Professor Liu Jing added.