Recently, Christina Psaroudaki, a researcher at California Institute of Technology, and Christos Panagopoulos, a professor at Nanyang Technological University, put forward the idea of using Sigming as qubit, and said that it has advantages in practicality and scalability.
The research paper was published in Physical Review Express on August 4th, local time, titled "Skyrmion qubits: a new class of quantum logic elements based on nanometer magnetization".
"Quantum computing is expected to significantly improve computing power through the inherent characteristics of quantum mechanics, surpassing today’s supercomputers." In an exclusive interview with The Paper (www.thepaper.cn), Psaroudaki said, "Quantum computers are based on qubits, which are represented by the special quantum state of a physical system. Unlike the 0 or 1 of classical bits, quantum bits can also be in the so-called superposition state-that is, both 0 and 1. In order to realize quantum computers, many different candidates are currently being sought. "
The paper shows that the core of quantum computing is qubit made of very small particles such as atoms, ions or electrons. At present, superconducting circuit is one of the leaders of noisy medium-scale quantum computing scheme. Its size is macroscopic, but it has perfect quantum characteristics. Although superconducting quantum has made great progress, there are still great challenges, especially in control and scalability.
In magnetic materials, when the spin orientation of local atoms deviates, a quasi-particle with vortex structure will be produced, which is called magnetic sigmon. The properties of this quasi-particle can generally be described by topological charge or helicity.
"Sigmon has 1/2 spin, so it can be used as a qubit. Because of its good stability, controllability and measurability, it can be used as a logical qubit in quantum computing. The so-called logical qubit refers to the unit that can realize the function of qubit logically and consistently, and the physical deviation and failure probability have little influence. " Zhao Yukang, an industry expert of Guo Dun Quantum, told a reporter from The Paper (www.thepaper.cn).
"Magnetic Sigming can be very small, reaching the nanometer level, and it is a candidate for the next generation of information storage and logic technology. Magnetic Smirnology is a field that deals with the development of classical Smirnon spintronics, and it has developed into a huge and active research field. " Psaroudaki said, "An important feature of our proposal is to accelerate the development of Sigmund quantum bits by using the knowledge and the most advanced technology in the field of Sigmund. The knowledge and technology of Sigmund can be directly used and transferred to our proposed platform, and it provides advantages in practicality and scalability. "
Sigmon qubit
The scheme proposed by Psaroudaki and Panagopoulos is to realize qubits by using stable magnetic sigmons bound in magnetic nano-disks, and to connect different magnetic nano-disks by using electric fields.
By applying the electromagnetic field, the discrete energy levels in the quantized energy spectrum of the magnetic Sigmon can be controlled, so that the helicity between different energy levels can be changed, and these two energy levels can be encoded into two quantum states |0 > and |1 > of the qubit. In addition, the electromagnetic field can be tuned to control the coherence time of qubits. In this design, the quantum bits of adjacent magnetic nano-disks can also be coupled with each other, thus realizing two-bit quantum gate operation. Finally, the reading operation of quantum information can be completed by using a high-sensitivity magnetometer.
A member of the domestic quantum team gave a detailed introduction to the reporter of The Paper (www.thepaper.cn) on how the magnetic sigmoid in this research is used in quantum computation. He said, "This paper uses the quantum computation of the spin angle φ in the XY plane, a quasi-particle of magnetic sigmoid. According to the different parameters, it is divided into two bit theory designs. "
"The first is to encode the qubit state by using the deviation of the spin component in the z direction from the equilibrium state, and the deviation of 0 or 1 represents the 0 or 1 state of the qubit respectively. This design is similar to the charge qubit in superconducting bits, and the bit state is encoded by the number of charges on the island. The second is to encode the qubit state by using the rotation angle of spin in XY plane. The two angles in opposite directions represent the zero state or the one state of the qubit respectively. This design is similar to the magnetic flux bits in superconducting bits, and the quantum bits are encoded by clockwise and counterclockwise currents. " The member said.
Psaroudaki said that because the sigmons can be manipulated by electric and magnetic fields, the quantum bit properties of multiple sigmons are configurable and can be optimized. This includes logical qubit state and qubit lifetime, which are very important to realize stable and reliable qubits and can perform various logical operations. "Our work shows that the Sigmund quantum bit is very attractive as a logical element of quantum processor, and it is coping with the key challenges of quantum bit technology-control and scalability."
The paper shows that scalability, controllability of microwave field, operating time scale and non-volatile readout technology are all together, which makes the Sigmund qubit very attractive as a logic element of quantum processor.
At present, Psaroudaki and Panagopoulos have found several candidate materials, which can be used to design artificially adjustable magnetic Sigmon qubits. They predict that with the development of research, more materials will emerge in the future to realize this kind of magnetic sigmoid qubit.
When talking about the prospects and challenges of Sigmund in the field of quantum computing, Psaroudaki said, "Our work is at the intersection of two unrelated research directions-the quantum bit field and the Sigmund field. The former aims at developing quantum computers, while the latter aims at designing future spintronics devices based on magnetic Sigmund. Our idea has introduced a new direction in the field of Siegel electronics and nano-magnetism, and opened up an undeveloped way for quantum computing. The challenge now is practicality, that is, designing architecture for specific functions. "
"This paper constructs quantum bits on two-dimensional magnetic materials, which is really meaningful in physics and creates a new realization method of quantum computing. However, because this is a relatively theoretical article, the discussion of single-bit self-state, single-bit manipulation, inter-bit coupling and bit state reading still stays at the physical level, not at the actual design level. " The aforementioned members of the domestic quantum computing team said.
Zhao Yukang said, "The work of this paper is to experiment the logic gate manipulation ability of a single sigmoid, which is a new possible route of quantum computing, but there is still a gap from the realization, such as the coupling that has not been extended to multiple sigmoids, and the verification of the deterministic manipulation and long-term retention ability of logical qubits is not sufficient."
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