2021-2022学年高二物理竞赛课件：量子比特的物理实现.pptx

量子比特的物理实现2易控制易控制超导约瑟夫森结，超导约瑟夫森结，SQUID原子，囚禁离子原子，囚禁离子液态，光子液态，光子量子点，量子阱量子点，量子阱固体核自旋等固体核自旋等 20022002年以来，超导比特的相干性得到极大改进年以来，超导比特的相干性得到极大改进可规模化可规模化相干性相干性量子比特的物理实现34HOW DO THEY WORK?Require quantum hardware:quantum bits(qubits).Then:Prepares an initial state.Executes a program(sequence of physical actions on the qubits).Make a final measurement.The key:During the execution of the program the quantum computer explores many classical computations(quantum paralelism)Quantum computersWHAT ARE THEY GOOD FOR?They could do everything a classical computer can do.(not very interesting)A FEW quantum algorithms are much more efficient than their classical counterparts:find prime factors of integer numbers(Shor).perform simulations of natural systems(physics simulations)search databases(Grover)?HOW DO THEY LOOK(very primitive)David DeutschRichard FeynmanPeter Shor19811990199461997，量子计算机的NMR实验方案1998，NMR量子计算实验演示1999，各种实验方案的提出，容错纠错码2000，NMR：5个比特的算法演示（IBM），7个比特的量子态的制备；固体硅基半导体NMR取得大的进展；2001，线性光学量子计算方案Quantum computers7Nuclear magnetic resonance-量子计算机量子计算机8n n位位NobelNobel奖得主奖得主1944 Rabi1952 Bloch1952 Purcell1955 Lamb1964 Townes1966 Kastler1977 VanVleck1981 Blowmbergen1983 Taube1989 Ramsey1991 Ernst9NMR-NMR-实验实验101112核磁共振量子计算核磁共振量子计算Deutsch algorithmdemonstrated.1H13CClClCl13(Vandersypen,Steffen,Breyta,Yannoni,Cleve,Chuang,July 2000 Physical Rev.Lett.)5 5 个比特个比特 215 Hz 215 Hz 量子处理器量子处理器 5-spin molecule synthesized Pathway to 7-9 qubits First demonstration of a fast 5-qubit algorithm14测量谱测量谱 r=1:1 line r=2:4 lines r=4:16 lines r=3:zero areaIdeally:15技术特点技术特点Nucleus magnetic moment as qubitControlled by EM waveMeasured by Nuclear magnetic resonance 2C+5F=7 qubits Not enough qubits