复杂动力学量子计算中的测量与信息提取

There and back again: A circuit extraction tale

Translations between the quantum circuit model and the measurement-based one-way model are useful for verification and optimisation of quantum computations. They make crucial use of a property known as gflow. While gflow is defined for one-way computations allowing measurements in three different planes of the Bloch sphere, most research so far has focused on computations containing only measurements in the XY-plane. Here, we give the first circuit-extraction algorithm to work for one-way computations containing measurements in all three planes and having gflow. The algorithm is efficient and …

Energy cost of entanglement extraction in complex quantum systems

What is the energy cost of extracting entanglement from complex quantum systems? In other words, given a state of a quantum system, how much energy does it cost to extract m EPR pairs? This is an important question, particularly for quantum field theories where the vacuum is generally highly entangled. Here we build a theory to understand the energy cost of entanglement extraction. First, we apply it to a toy model, and then we define the entanglement temperature, which relates the energy cost to the amount of extracted entanglement. Next, we give a physical argument to find the energy cost of…

Parallel syndrome extraction with shared flag qubits for Calderbank-Shor-Steane codes of distance three

To perform achieve fault-tolerant quantum computation, one can use flagged syndrome extraction with fewer ancilla qubits. However, it suffers from long circuit depth if one stabilizer is measured at a time. Previously, Reichardt showed that it is possible to measure multiple stabilizers with at most one shared flag qubit for certain small quantum codes. In this paper, we propose a procedure for general Calderbank-Shor-Steane codes of distance three so that multiple $Z$-stabilizers ($X$-stabilizers) can be fault-tolerantly measured in parallel with one shared flag qubit. We simulate the memory …

多模OPA光中的量子优势资源：识别、优化与提取

The quantum-advantage resource in multimode OPA light: Identification, optimization, extraction

提出混合多模高斯态中量子复杂性资源的概念，通过凸优化和光子数统计定量表征量子优势，并优化脉冲OPA生成和提取数千个纠缠压缩模。

计算功提取：催化剂的复杂性

Computational Work Extraction: The Complexity of Catalysts

本研究证明量子系统中催化剂能极大提升计算功提取效率，实现全部遍历功提取，而非催化过程提取可忽略，并引入伪遍历功概念，揭示催化计算与遍历功的深层联系。

黑箱功提取的样本复杂度

Sample Complexity of Black Box Work Extraction

针对未知量子态功提取因量子层析低效而困难的问题，本文分析了样本复杂度，证明单拷贝下可提取功渐近为零，多拷贝下建立了精度与成功概率的标度关系，提出样本高效的量子电池效用评估协议并开辟近期量子计算热力学量估计新方向。