Practical large-scale quantum computers require active error correction, but for this to work, the components must reach fidelities that are very challenging. In this theory paper, we customise the leading ‘surface code’ approach, layering it on top of a second simpler code to detect the most common noise type. Information Read more…
In general, metrology aims to increase the precision of measuring a physical quantity, such as time or the strength of a magnetic or electric field. This precision is typically limited by statistical errors and can be enhanced by repeating experiments many times and averaging their results. Quantum metrology takes fundamental Read more…
QTechTheory welcomes its newest member Bálint Koczor, joining as a postdoctoral researcher! Bálint is supported both the EU Flagship project AQTION, visit the website here.
We develop a completely new variational quantum algorithms for simulating general processes, one of which can compute the general matrix multiplication to a vector, while the other is for simulating the general first order derivative equation. These algorithms appear to have a large amount of applications, such as quantum machine Read more…
Several of the group’s papers in the last year have focused on the theory behind so-called hybrid quantum algorithms — where a conventional computer and a quantum coprocessor work in tandem. These methods are typically variational because the quantum machine has a number of parameters (essentially, knobs that can be Read more…
Working with Alexander Mayorov from Cambridge and Xiao Shan from Oxford Chemistry, we’ve looked into the prospects for modelling molecular vibrations using a quantum computer. Vibrations are are the core of many important phenomena such as spectral properties, energy transfer, and molecular bonding — but they are hard to model Read more…
Together with Alán Aspuru-Guzik, our group has put together a pretty comprehensive review of quantum computers for chemistry simulation. It’s written with examples and aimed at allowing people from either community to get to grips with this exciting interdisciplinary area. We just updated the arxiv version so it’s a good Read more…
To run a program, a computer needs to understand how to perform each operation written in the code. But there are possibly thousands of programming languages which contain extremely many basic operations. How can one computer run them all? It can do so using compilers: Software written in a language the Read more…
The hamiltonian simulation is to simulate the dynamics of the system, given some Hamiltonian. The conventional way of the Hamiltonian simulation is the Trotter decomposition. We discretize the simulated time to small time steps, like the classical Runge–Kutta method. Although if we increase the steps of the discretization, we can Read more…
For quantum error correction, if the error rate of our physical components is below a certain error threshold, we can decrease the overall computational error indefinitely by scaling up the code. To obtain the value of such a threshold, we need to simulate the quantum error correction circuit, which can only be Read more…