Synopsis: Simulating a molecule

An NMR-based quantum computer can simulate a hydrogen molecule and accurately yield its ground-state energy.
Synopsis figure
Illustration: J. Du et al., Phys. Rev. Lett (2010)

In the early 1980s, Richard Feynman proposed using a computer that followed the rules of quantum mechanics to mimic a physical system—not in the way digital computers perform numerical simulations, but something closer in spirit to an analog computer where expectation values of some quantum subunit were the “readout.”

Today, we know these devices as quantum computers and intense efforts are focused on scaling them up to make useful computational devices. But investigations into Feynman’s original notion of quantum computers as “quantum simulators” still exist. Several groups have reported results with quantum computers based on nuclear magnetic resonance (NMR) and ion-trap methods, including molecular simulators that calculate molecular energy levels.

Writing in Physical Review Letters, Jiangfeng Du and colleagues at the Hefei National Lab for Physical Sciences at the Microscale in China report their work on using a quantum computer to simulate a hydrogen molecule. The simulation is performed with NMR-based quantum information processing: isotopically labeled chloroform molecules act as the processing medium, with 13C serving as the system qubit. By applying a sequence of NMR pulses to the chloroform, Du et al. can prepare an initial state of the carbon, manipulate the qubits in a controlled way, and read out the qubit phase shifts to generate a value for the ground-state energy of a hydrogen molecule. Although only a proof-of-principle on a test case, Du et al. are able to carry out the computation with 45-bit precision and show the potential for quantum information processing in quantum chemistry calculations. – David Voss


Features

More Features »

Announcements

More Announcements »

Subject Areas

Atomic and Molecular PhysicsQuantum Information

Previous Synopsis

Atomic and Molecular Physics

Opening the gate to quantum computation

Read More »

Next Synopsis

Related Articles

Synopsis: Detecting a Molecular Duet
Atomic and Molecular Physics

Synopsis: Detecting a Molecular Duet

Using a scanning tunneling microscope, researchers detect coupled vibrations between two molecules. Read More »

Viewpoint: How to Create a Time Crystal
Atomic and Molecular Physics

Viewpoint: How to Create a Time Crystal

A detailed theoretical recipe for making time crystals has been unveiled and swiftly implemented by two groups using vastly different experimental systems. Read More »

Viewpoint: What Goes Up Must Come Down
Atomic and Molecular Physics

Viewpoint: What Goes Up Must Come Down

A molecular fountain, which launches molecules rather than atoms and allows them to be observed for long times, has been demonstrated for the first time. Read More »

More Articles