Large-scale quantum walks via complex polarization transformations
Location: QNC 0101
How can two parties carry out a fair coin flip across a noiseless quantum channel? In 2007, Carlos Mochon proved a tantalizing result: he showed that fair quantum coin flipping is possible in principle, but he used a protocol that required a huge (exponential) number of communication rounds. In the twelve years since, despite some continued deep theoretical work on the problem, no improvements to the efficiency of Mochon's protocol have been made.
Interference is an essential part of quantum mechanics. However, an important class of Hamiltonians considered are those with "no sign problem", where all off-diagonal matrix elements of the Hamiltonian are non-negative. This means that the ground state wave function can be chosen to have all amplitudes real and positive.
A vibrant program has formed in recent years in various scientific disciplines to take advantage of near-term and future quantum-simulation and quantum-computing hardware to study complex quantum many-body systems, building upon the vision of Richard Feynman for quantum simulation.
The ability to store and manipulate quantum information encoded in electromagnetic (often optical) signals represents one of the key tasks for quantum communications and computation schemes.
The three main branches of quantum algorithms, for simulation, search, and factoring, hold historically disparate origins. Today, we can now understand and appreciate all of these as being instances of the quantum singular value transformation algorithm of Gilyen, Su, Low, and Weibe. This unified framework, and the surprisingly universal role of single-qubit dynamics, open doors to many new quantum algorithms and opportunities for quantum advantage.
The recording is now available online.
Parametric couplings offers the exciting possibility to manipulate and control interactions between engineered quantum systems. Such systems are artificial mesoscopic systems whose dynamics are governed by the laws of quantum mechanics. Prominent examples of these mesoscopic systems are ultracold trapped atoms and ions, superconducting circuits and electro/optomechanical systems.
The success of superconducting quantum computing (SQC) has so far been largely built upon the transmon qubit. Finding an alternative qubit that drastically outperforms transmon represents one of the most fundamental and exciting frontiers of SQC. The fluxonium qubit stands out as a promising candidate, due to its long coherence times and large anharmonicity. Furthermore, fluxonium can be directly integrated into the existing circuit-QED schemes for scaling.
Quantum Today is an exciting new seminar series that pulls its themes from recently published scientific articles. Join us as we sit down in conversation with researchers to talk about their work, what’s the impact and where their research will lead to.
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