A new study provides new clues for how the information in the superconductant quantum bit is lost.
Written text | Jin Yirong
Today, talk about something that the world is very concerned -superconductant quantum BitbitEssence
We know that quantum computing may bring us incredible index level calculation acceleration and inject infinite imagination into our future.And its most basic unit is called a quantum bit.Quantum Bit is the simplest quantum system, it has only two energy levels -you can simply understand that two energy status (Note: energy level can be understood as a energy state of the quantum system, different from the classic system -its energy -its energyIt can change continuously. The energy status of the quantum system is discontinuous, which is "first -level and one level", which is why we call it "quantum").
However, as the classic calculation house is based on the simplest logical unit- "switch", the circuit formed by tens of billions of switches can complete such an incredible job today, thenThe circuit formed by a large number of quantum bits, plus the "BUFF" unique to quantum -superimposed and entanglement, what can be done is beyond imagination.Therefore, building a "good" quantum bit has become one of the most critical tasks to achieve quantum computing .So how to build it?Definitely start with the material.In the micro -world, if you want to find the material to build a quantum bit, that is, a pair of quantum energy levels is actually not difficult, and it can even be said to be everywhere.For a few examples, any atoms, the electrons around the atomic nucleus have infinite multiple levels. Two of them can be regarded as a quantum bit.There are two types: upward or down, it is simply a natural quantum bit; in micro -systems such as photons, nuclei, molecules, etc., quantum bits can be constructed. Such examples are endless.However, the protagonist superconductant quantum Bit is an exception.It is not in micro particles, but constructing quantum bits in the macro device .Its quantum state is not the state of a certain particle, but a certain collective state formed by a large number of particles.What is naturally heterogeneous and make it so popular?
First of all, superconductant quantum bits are solid devices , that is, it can be printed on the chip like a transistor.This brings two benefits. The first is naturally facilitating integration and expansion. This is the key to the semiconductor transistor that can rule the classic calculation world.The other is that its position is fixed.This advantage is that only those who have done micro -particle quantum bits will have experience.Take the electronic spinning mentioned earlier as an example. It is indeed a natural quantum bit, but the electrons are too light and active. It is difficult to grab the electrons.Control them.It was not until today we found a better way to grab the atoms and let them arrange them. These atoms still run away without paying attention.This is not a problem for superconducting quantum -like solid devices.It is a fat cat of Xue Dingzheng, lying there, providing great convenience for manipulation and measurement.
Secondly, superconductant quantum bits are based on macro quantum state .Corresponding to the micro, macro refers to the acts of collective participation in a large number of particles. Among the superconductant quantum bits, there are millions to hundreds of millpieces.) On the contrary, the electrons that attract each other with the help of the crystal vibration (sound -vibration). After pairing, the spin is zero and has a boson properties.——Surious.] It is bound in a circuit formed by Josephson knot and capacitor/inductance.What are the benefits of this?First of all, the interaction between a single particle and the external electromagnetic field is extremely weak. When a large number of particles are together, the intensity of interaction is greatly enlarged, so is easier to control and measure ;It is easier to couple, which means that we can easy to entangle together.In short, Xue Dingzhengs cat in superconducting quantum is very large, so it is much easier to get up.
Talk about the benefits, its time to talk about the problem.It is because Xue Dingzhengs fat cat is too big, it is more vulnerable to other unrelated factors .There are too many "irrelevant" factors in solids, and they are also macroex.This has led to the "life" of superconductant quantum bits. .In a wave of fingers, for superconducting quantum bits, it is already as bad as the sea.The life of the first superconducting quantum bit is only a few seconds. After more than 20 years of efforts, it has now only increased to a micro seconds to millisecondweight.Compared to much shorter.Fortunately, the control time of superconductant quantum bites is also very short. The two are offset, and the performance is not weak than the quantum such as ion trap.
No matter what, improving the life of quantum bites has always been an extremely important research theme.The most critical part of superconductant quantum Bit is Josephson. It is important to understand how the scattered mechanism is, that is, how energy or information is lost, and it is very important to disappear in the "vast hot sea".We have figured out that we have retreated mechanisms such as charges, magnetic flux rising, and quasi -particle tunnels, and designed quantum bits with long lifelong life like transmon and Fluxonium on the basis of these cognitions.
In August 2024, the team from the University of Alto from Finland used extremely precise thermal electronic radiation meters to study how the oscillating current in Josephson turned into calories.In different bias areas, the team measured different dispersal behaviors and corresponds to different energy dispersion mechanisms.The research team also established a circuit model to explain the experimental results and capture the dynamic behavior of Josephson knot and its surrounding environment.This radiation measurement detection method provides a more sensitive tool for studying Josephson dynamics than traditional electrical measurement methods.Experimental broadband detection capabilities provide new possibilities for exploring quantum phenomena and increasing the coherence of superconductant quantum bites.It is of great significance to both quantum computing and quantum measurement.
As we understand the more deeper understanding of superconductant quantum materials and micro mechanisms, I believe that in the future, we can make quantum bits with longer life.Combined with the progress of quantum error correction, we are getting closer and closer to the era of general quantum computing.
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