Building a quantum computer

Jonathan DuBois

One of the most intriguing—and extraordinarily difficult—challenges in scientific research is building a practical quantum computer. Today, corporations such as IBM, Google and Intel as well as a handful of startups and leading universities are racing to make quantum computing a reality. Lawrence Livermore physicist Jonathan DuBois heads the Quantum Coherent Device Physics Group, which aims to be among the first to build a useful quantum computer and determine the best applications that would benefit from such a revolutionary device.

Jonathan’s group operates a quantum computing testbed facility that features a prototype 3-meter-tall cylindrical quantum computing device with a sapphire chip suspended inside. The device is kept inside a refrigerated and gold-plated vacuum chamber at temperatures colder than outer space (-273.14 degrees C or seven thousandths of a degree above absolute zero).The researchers are using the prototype to develop, among other things, useful algorithms for solving quantum simulation problems.

Jonathan explains that while “classical computers” encode information in 1s and 0s (essentially on/off switches), quantum computers are based on qubits, which can exist in an infinite number of states. While it’s doubtful quantum computers will replace classical computers, such as the enormously powerful supercomputers residing at Lawrence Livermore’s Computing Complex, scientists believe quantum machines will solve certain complex problems much faster. The machines would also be ideal for handling problems that overwhelm existing supercomputers, such as revealing the dynamics of chemical reactions, nuclear structure, and other national security applications. Another idea is pairing a quantum “co-processor” to a conventional supercomputer to drastically speed up certain calculations.

Jonathan received a PhD in Condensed Matter Theory from the University of Delaware, followed by postdoc appointments at University of California at Berkeley and Lawrence Livermore. He notes that although he is trained as a theoretician, his group is composed largely of experimentalists, a situation that could happen “only at Livermore,” where multidisciplinary teams are the norm. He describes Livermore’s research environment as combining the best features of a startup company, university, and corporation.

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Building a quantum computer