Huawei's patent for superconducting quantum chip approved to reduce crosstalk between quantum bits

On November 1, according to the State Intellectual Property Office of China Patent Publication Notice, Huawei Technologies' "superconducting quantum chip" patent was approved (application publication number: CN115271077A).

01New superconducting quantum chip: reduces crosstalk between quantum bits

This time, the new patent is called "superconducting quantum chip".

The patent abstract describes that: embodiments of the invention disclose a superconducting quantum chip, including a coupler and a controller; wherein the coupler is used to couple a first superconducting bit circuit and a second superconducting bit circuit, and the frequency response curve of the coupler includes at least one phase reversal point, and said phase reversal point includes a resonance point or a pole of the frequency response curve; the controller is used to adjust the frequency response curve of said coupler, so that said first superconducting bit circuit contains an odd number of said phase reversal points between the bit frequencies of said first superconducting bit circuit and the bit frequencies of said second superconducting bit circuit; and further adjusting the frequency of said phase reversal points such that the equivalent interaction of the cross-resonance effect of said first superconducting bit circuit and said second superconducting bit circuit is zero.

The claims indicate that "embodiments of the present invention reduce crosstalk between quantum bits."

2Specific embodiments

In order to make the purpose, technical solutions and advantages of the present invention clearer, the following embodiments will be described in further detail in conjunction with the accompanying drawings.

Embodiments of the present invention provide a quantum computer comprising: a dilution chiller for providing a low temperature environment, a superconducting quantum chip for implementing a quantum computing information carrier, and a measurement and control system for manipulating a quantum bit state for a computing operation and reading a quantum bit state.

The superconducting quantum chip is placed in the cryogenic environment, and the measurement and control system controls the microwave source and the modulated pulse signal according to the requirements of the computational operation, and inputs a series of microwave pulse sequences to the superconducting quantum chip to manipulate the bit quantum state. After all the operations are completed, the measurement and control system then outputs the measurement pulse signals to the superconducting quantum chip and obtains the quantum bit state information through the returned signals to obtain the calculation results.

A schematic diagram of the structure of a quantum computer system provided by an embodiment of the present invention

As shown in the figure below, a superconducting quantum chip is provided for an embodiment of the present invention, including a two-dimensional array arrangement of superconducting bit circuits, and a coupler that couples the superconducting bit circuits together. The two-dimensional array arrangement is currently the most promising bit arrangement structure required for quantum error correction codes, including surface codes. In order to implement surface code error correction on a chip with a two-dimensional array arrangement, the error in the two-bit logic gate needs to be less than 1%.

A schematic diagram of a superconducting quantum chip structure provided by an embodiment of the present invention

Two superconducting bit circuits are coupled to each other by a coupler. The S21 frequency response curve of the entire coupler can be changed by adjusting part of the inductance or capacitance in the coupling circuit by a control signal, such as current or voltage, which adjusts the frequency of the resonance point (mode) or pole (pole) in the frequency response curve. Embodiments of the present invention provide solutions that greatly reduce the crosstalk between superconducting bit circuits by shutting down the coupling between them, while placing no significant restrictions on the layout of the space between superconducting bit circuits, and allowing the design of adjustable coupling circuits with longer physical lengths for increasing the wiring space between bit circuits.

This embodiment of the invention greatly enhances the scalability of the architecture and is beneficial to further increase the number of bits integrated in superconducting quantum chips.

03Huawei continues to make efforts in superconducting quantum computing

Huawei began to frequently explore the direction of chip development, and before this announcement of quantum chip patents, Huawei also announced two patents related to chip stacking. Huawei has been laying out quantum computing since 2017, and in recent years has disclosed "a quantum chip and quantum computer", "a method for controlling quantum bits in a superconducting chip and related devices", "superconducting quantum computing system and quantum bit manipulation method" and so on.

Whether it is a quantum chip or quantum communication, Huawei's exploration of the layout proves that it will continue to move forward in the quantum field, and there is a trend of accelerating progress.