We discuss a device capable of filtering out two-mode states of light with mode populations differing by more than a certain threshold, while not revealing which mode is more populated. It would allow engineering of macroscopic quantum states of light in a way which is preserving specific superpositions. As a result, it would enhance optical phase estimation with these states. We propose an optical scheme, which is a relatively simple, albeit non-ideal, operational implementation of such a filter.
NMR (Nuclear Magnetic Resonance) is a versatile probe of condensed matter, and has a broad range of applications in chemistry, medicine (MRI), oil industry, etc. NMR has become so popular outside the conventional realm of physics that the crucial role NMR has been playing in condensed matter physics is sometimes overlooked. I will explain how condensed matter physicists use NMR as a powerful low energy probe of solids, drawing examples from modern research into statistical physics, magnetism, and superconductivity.
We provide a quantum algorithm for simulating the
dynamics of sparse Hamiltonians with complexity sublogarithmic in
the inverse error, an exponential improvement over previous methods.
Unlike previous approaches based on product formulas, the query
complexity is independent of the number of qubits acted on, and for
time-varying Hamiltonians, the gate complexity is logarithmic in the
norm of the derivative of the Hamiltonian. Our algorithm is based on
a significantly improved simulation of the continuous- and
We introduce the notion of strong quantum speedup. To compute this
speedup one must know the classical computational complexity. What is it about the problems of quantum physics and quantum chemistry that enable us to get lower bounds on the classical complexity?
The Institute for Quantum Computing's (IQC) Grad Student Association is screening the 7 Academy Award winning movie Gravity on April 2nd at 7 pm. The event will be followed by a short presentation and Q&A with IQC's associate member, astronaut, and former Canadian Space Agency president Steve MacLean.
