Quantum computing can be so fast because the underlying operational logic is completely different from that of electronic computers.
In the Internet era we live in today, its underlying logic is based on one-way running binaries.
The core of a traditional computer is the CPU, and the essence of the CPU is a large controller composed of countless transistors. Each transistor is like a switch, representing 0 and 1 through the opening and closing of the switch and the binary combination of 0 and 1. Any numbers, letters, and pixels can be represented. Therefore, the text and photos presented on the screen can be represented by the most basic combination of 0 and 1.
But the combination of 0 and 1 is a linear process. The length of the combination of 0 and 1 will be longer to express more information.
When a classic CPU processes binary, it can only process one operation simultaneously. The more information, the longer the CPU processing time.
Quantum computers are fast because they no longer use the seemingly simple linear operation method of binary but use quantum bits, that is, qubits.
Many people may be unfamiliar with qubits, but fans who often watch my videos must have a certain understanding of quantum mechanics.
Quantum mechanics is a subject that studies the microcosm. Specifically, the microcosm is the subatomic world, the space-time composed of particles smaller than atoms.
The movement of microscopic particles is completely different from that of macroscopic objects. Microscopic particles have wave-particle duality and quantum superposition state.
In layman’s terms, microscopic particles can be in multiple locations simultaneously. Position distributions can spread throughout the universe. This causes microscopic particles to behave like waves. The wave’s energy usually gathers at a specific scale, forming a wave packet. We refer to this state as the particle state. The microscopic particle will resemble a wave if the packet is spread out. This is the embodiment of particle-wave-particle duality.
In essence, the intrinsic properties of microscopic particles are fuzzy and uncertain. This property also creates the peculiar phenomenon of quantum superposition.
Quantum superposition is the quantum state of a quantum system, which can be any of several different quantum states. In layman’s terms, a particle can be in multiple states before measurement, such as the spin of an electron, which has intrinsic angular momentum. Performance: Before measurement, the electron can be in the up-spin or down-spin states. Once the electron’s spin is measured, it is either up spin or down spin, and the superposition state will disappear.
The essence of quantum computers is to use the characteristics of microscopic particles that can be in a superposition state.
The quantum superposition of microscopic particles is fragile because it can be disrupted by external energy, causing the collapse of the superposition state. This collapse is known as quantum decoherence, where the particles transition from a quantum state to a classical state.
To run a quantum computer continuously, you must keep the particles in a superposition state. This requires a highly demanding external environment.
Quantum computers need to be kept in a specialized cooling system like a refrigerator. This system maintains a very low temperature above absolute zero to avoid interference from outside particles.
Only in this way can the superposition state of particles be maintained continuously!
The spin superposition state of a qubit represents 0 and 1. Before operating on the qubit, the qubit can be in any state of 0 and 1.
In fact, qubits can be replaced by any basic particles, such as electrons and photons. This is because microscopic particles all have superposition states, and it does not matter which particle is used. However, considering the difficulty of operating particles and the cost of production, we generally use photons as the basic particles for quantum computing.
Mathematically, we can write the superposition state as │ψ>, where psi represents the wave function, which represents the superposition of qubits, α square represents the probability that the superposition state is 0, and β square represents the probability that the superposition state is 1. But no matter what, the probability of 0 or 1 must be 100%.
So, the square of α plus the square of β must equal 1. In binary in classical computers, if we choose α to be 1, then β must be zero. Vice versa.
But in a quantum computer, as long as α²+β²=1 is satisfied, α and β can take any value between 0 and 1 under the premise of the formula. For example, when α is 1/√2, the value of β is 1/√2.
The values of α and β can take any value if the formula satisfies. This allows them to handle countless problems theoretically.
For example, a corresponding result is output when the input qubit is 1. When the input qubit is 0, another result is output. In addition, the corresponding result will be output when the input qubit is at any number between 0 and 1. So, we can simultaneously process any numerical operation between 0 and 1 through the superposition of qubits.
Quantum computers cannot be measured while running, which would collapse the superposition state and lead to issues. The output result is presented as a probability. And if we want to deal with problems through quantum computers, we must get definite, that is, classical results. Otherwise, the results of quantum computing operations will create a messy data situation.
Quantum programming scientists must enhance the likelihood of precise answers by employing remarkably complex and sophisticated design programs. This is quantum error correction.
So, what should we do to improve the ability of quantum error correction?
To increase the chance of getting the correct answer from the superposition state, we need to intentionally and precisely interfere with the wrong outcomes, eliminating them and improving the probability of obtaining the accurate answer. This is because the superposition state behaves like a wave.
Stronger quantum error correction improves the probability of correct answers in quantum computing, enabling commercialization.