The quantum world is different from the familiar world. The most famous thought experiment in quantum physics is Schrodinger's cat. Imagine that we seal a cat in a box. The fate of cats is linked to the quantum world through a poison. Only when radioactive atoms decay will the fate of cats be released. According to the theory of quantum mechanics, atoms must exist in a strange state called superposition state, which has decayed and has not decayed before being observed. In addition, because cats' survival depends on the action of atoms, it seems that cats must exist in the form of a superposition of live cats and dead cats before someone opens the box to observe them. After all, the cat's life and death depend on the state of the atom, and the state of the atom has not yet been decided.
However, no one really believes that cats can be both dead and alive. Elementary particles, such as atoms, do strange quantum things, exist in two states at the same time, occupy two positions at the same time, cross impenetrable barriers and so on. This is very different from the classic objects we are familiar with, such as cats.
Quantum mechanics insists that all particles are also waves. But if you want to see strange quantum effects, the waves should be lined up so that the peaks and valleys coincide. Physicists call this property coherence: just like the tonality of notes. If the waves don't line up, the peaks and valleys will cancel each other out, destroying the coherence, and you won't see anything strange. On the other hand, when you only deal with the wave of a single particle, it is easy to keep its "tonality", and it must only be consistent with itself. But it is impossible to line up waves of hundreds, millions or trillions of particles. So the strangeness inside the big object will be offset. That's why cats don't seem to be uncertain.
However, in 1944, what is life written by Schrodinger? "Some of the most basic components of life, such as unobserved radioactive atoms, must be quantum entities that can perform counterintuitive skills."
He thinks that life is different from the inanimate world, because it lives at the boundary between the quantum world and the classical world, which we can call the quantum edge.
Schrodinger's argument is based on a seemingly contradictory fact, that is, although they seem to be orderly, all classical laws, from Newtonian mechanics to thermodynamics to electromagnetism, are ultimately based on disorder. Imagine a balloon: it is filled with trillions of air molecules, all of which move randomly and collide with the skin of the balloon. However, when you average their movements, you get the gas law, which can accurately predict, for example, that a balloon will expand by a certain amount when it is heated. Schrodinger called this law "order in disorder" to reflect that macroscopic regularity depends on the chaos and unpredictability of a single particle.
What does this have to do with life? At that time, the physical properties of genes were still mysterious. Even so, people still know that it must be passed down with extraordinary high fidelity: the error is less than one billion. And the gene is very small. Schrodinger insists that the accuracy of gene replication cannot depend on the rules of the classical world from disorder to order. He suggested that they must involve a "more complex organic molecule", in which "each atom and each group of atoms play a separate role".
Schrodinger called these novel structures "periodic crystals". He asserted that they must obey quantum laws rather than classical laws, and further suggested that gene mutations may be caused by quantum transitions in crystals. In addition, many characteristics of life may be based on a new physical principle.
We can see that in an inanimate world, macro-order usually comes from molecular disorder, and order comes from disorder. But Schrodinger believes that the macro-order we find in our life reflects something else: the incredible order on the quantum scale. He called this new speculative principle "order from order".
Is he right?
Ten years later, the veil of the double helix was untied. Genes are originally composed of single-molecule DNA, which is a molecular chain of nucleotide bases (genetic letters) strung together like beads. This is a photoperiod crystal, worthy of the name. Moreover, as Schrodinger predicted, each group of atoms does play an independent role, and even the position of a single proton (a quantum property) determines each genetic letter. In the whole history of science, nothing is more prophetic. The color of your eyes, the shape of your nose, and all aspects of your personality, intelligence or disease tendency are encoded at the quantum level.
However, after the discovery of the double helix, molecular biology still mainly follows the concept of classical physics. In the second half of the 20th century, this played a very good role in the research of molecular biologists and biochemists, because molecular biologists and biochemists are concerned about things like metabolism, which is the product of a very large number of particles operating under the principle of order-disorder. However, with the attention of biology in 2 1 century turning to smaller and smaller systems, even single atoms and molecules in living cells, quantum mechanics once again makes people feel its existence.
Recent experiments show that some of the most basic life processes do depend on strange phenomena in the quantum world.
Just a few examples. For example, the sense of smell, the traditional sense of smell theory believes that odor molecules are detected by olfactory receptors through a mechanism similar to "lock and key" in the nasal cavity: molecules are inserted into the receptors and trigger a reaction, just like a key unlocking. This is a good intuitive theory, but it fails to explain some puzzling observations, for example, molecules with very similar shapes often smell different smells, and vice versa. One theory is that the receptor may be a response to molecular vibration, not a shape. This theory was confirmed by quantum theory in 1996. British biophysicist Lucas Turing suggested that vibration may promote the quantum tuning of electrons, thus unlocking the olfactory lock. The quantum theory of odor may sound crazy, but recently there is evidence to support this theory: it is found that fruit flies can distinguish odor substances with exactly the same shape but different isotopes and elements, which is difficult to explain without quantum mechanics.
As we all know, some birds and other animals find their direction by detecting the weak magnetic field on the earth. However, the mechanism by which they do this has always been a mystery. It is difficult for researchers to see how such a weak magnetic field can generate signals in animals.
It is found that the positioning system of European robin is related to light. Different from the traditional compass, it detects the angle of the magnetic field lines relative to the earth's surface, rather than the direction of the magnetic field lines. Nobody knew why at that time. In 1970s, German chemist Klaus Schulden discovered that some particles produced by chemical reactions kept in touch with each other through a strange quantum entanglement property. Entanglement keeps distant particles connected in an instant, no matter how far apart they are: they can be thrown at both ends of the galaxy, but still remain mysteriously related.
Quantum entanglement is so strange that Einstein himself described it as "a strange action at a distance". Hundreds of experiments have proved that it is true.
Schulten found that entangled particles are extremely sensitive to the strength and direction of magnetic field. He thinks that the positioning system of birds may use quantum entangled particles.
Few people take this idea seriously. But in 2000, Shulton and his student Tollsten Ritz wrote an influential paper, which showed how to use light to make a quantum five-pointed star compass in the eyes of birds. In 2004, Ritz cooperated with the famous couple ornithologists Wolfgang and Roswitha Wilts. Together, they found convincing experimental evidence that European robins are indeed using quantum entanglement mechanism.
As we all know, enzyme is the working "yeast" in the life world. They accelerate chemical reactions, so that chemical reactions that originally took thousands of years can occur in living cells in a few seconds. How the enzyme achieves this instantaneous rapid acceleration has always been a mystery. Studies by Judith Clingman of the University of California, Berkeley and Nigel Scranton of the University of Manchester show that enzymes can use a strange quantum technology called tunneling effect. Simply put, enzymes stimulate a process in which electrons and protons disappear from one position in biochemistry and then reappear in another position immediately without visiting anywhere in the middle. This is a remote transmission.
Enzyme is the most basic thing, which makes every biomacromolecule in every cell of all living things on earth. They are the basic components of life, more important than any other components, even more important than DNA, because some cells can survive without DNA. The quantum effect of enzymes helps us maintain life.
Let's take a look at photosynthesis, which is the most important biochemical reaction on earth. It is responsible for converting light, air, water and some minerals into grass, trees and grains, and finally into these people who eat plants. The initial event is that chlorophyll molecules capture light energy. These light energies are converted into electric energy and then transported to a biochemical factory called a reaction center, where they are used to fix carbon dioxide and convert it into plant matter. This energy transport process has always fascinated researchers because its efficiency is very high, close to 100%. Why can green leaves transport energy better than our most advanced technology?
Graham Fleming's laboratory at the University of California, Berkeley has been studying this problem for more than ten years. They used a technique called femtosecond spectroscopy to study this problem. The team used a very short laser to illuminate the photo combination to find the path for photons to reach the reaction center. As early as 2007, the team studied a bacterial system called FMO complex, and photon energy must find its way through chlorophyll molecular groups. It is considered as an electric particle, jumping from one chlorophyll molecule to another, just like Schrodinger's cat. The researchers found something unusual in the process. Due to the lack of any navigation, most photon energy should jump aimlessly in the wrong direction and eventually fall into the water. However, in plants and bacteria that carry out photosynthesis, almost all photon energy packets will reach the reaction center.
When the research team irradiated the laser to the system, they observed a very strange optical echo, which appeared in a rhythmic way. These quantum jumps are a signal that photon energy does not take a single route in the system, but uses quantum coherence to pass through all possible routes at the same time.
Imagine if Schrodinger's cat somehow divided itself into many identical quantum coherent cats when facing the stream, and they jumped over the chlorophyll boulder through various possible routes to find the fastest route. Now, scientists have detected quantum beats in many different optical systems, including the optical systems of traditional plants such as spinach.
If this doesn't convince you, let's finally talk about the evolutionary mechanism itself. Schrodinger pointed out that mutation may involve quantum jump. The transformation of nucleotide bases between different structures is called "isomorphism" and is considered to involve quantum tuning. 1999, Jim Al-Khaliri, a British physicist, thought that "proton tunneling" (protons disappear instantly at one site, and the same protons separated by barriers appear at adjacent sites) may be a very special mutation and an adaptive mutation. This mutation seems to occur more frequently when an advantage is provided. Researchers are currently trying to find experimental evidence of "proton tunneling" in DNA.
All these puzzling life phenomena have quantum effects. Quantum coherence is a very subtle phenomenon, which depends on tuned particle waves. To maintain it, physicists usually have to seal their systems in a nearly perfect vacuum and cool them to a temperature very close to absolute zero to freeze any thermally driven molecular motion. Molecular vibration is the deadly enemy of quantum coherence. So, how can life stay in warm and humid cells long enough to support its molecular order in order to perform its quantum skills in cells? This is still a profound mystery.