Classical simulations of quantum prepare and measure communication processes

Quantum communication has been shown to be vastly superior to classical communication in many problems. However no general statements exist which tells us how much better quantum communication is to its classical counterpart. In this thesis it was studied the minimum amount of classical bits required to exactly simulate a quantum communication...

Gate Set Tomography on the Nitrogen-Vacancy Center

In this thesis, gate set tomography (GST) has been conducted on the nitrogen vacancy center (NV). Gate set tomography is a protocol for characterization of logic operations (gates) on quantum computing processors. The NV’s electron served as a qubit. The quantum circuits were run both experimentally as well as on an NV-simulator. GST is...

Gate Set Tomography for Nitrogen-Vacancy Systems

Quantum computing is an emerging field with many promising future applications. <br/>These include, but are not limited to, quantum machine learning, quantum cryptography and quantum chemical engineering.<br/><br/>Before these can be realised, obstacles, which arise due to scaling, need to be overcome.<br/>To accomplish this, quantum processors...

Integrated entangling gates: Creating GHZ States for Stabilizer Measurements in Distributed Quantum Computing

High fidelity GHZ states among remote nodes is a precious commodity which can allow for non-local stabilizer measurements and thus pave the way for a modular fault-tolerant quantum computer. To this end, we extend the high fidelity intracavity gate introduced by Borregaard et al. (2015) to distributed paradigm, consisting of SnV-inspired atomic...

Hybrid one-way quantum repeater concatenated with the [[5,1,3]] code

An improvement to the existing one-way quantum repeater network using the tree cluster state as the quantum error correcting code is presented. Namely, the [[5,1,3]] quantum error correcting code is introduced as an outer code while the tree code becomes the inner code. Using this approach, we present a novel hybrid one-way quantum repeater...

Variational Quantum Algorithms: for Optimizing Probe States

As quantum computers are developing, they are beginning to become useful for practical applications, for example in the field of quantum metrology. In this work, a variational quantum algorithm is used to find an optimal probe state for measuring parameters in a noisy environment. This is achieved by optimizing a cost on a quantum computer,...

Characterizing qutrits and their noise environments

The standard toolbox of modeling and characterizing quantum systems comes with a standard set of assumptions as well. The two-level approximation replaces a many-level system with a qubit, and the Markovian approximation assumes an environment with a short memory. In this thesis, these assumptions are relaxed, and the dynamics of a single qutrit...

Improvements of the classical simulation of quantum circuits: Using graph states with local Cliffords

With this thesis project, we improve the classical simulation of quantum computers using stabilizers in the GSLC formalism. We do this in two ways: we present new algorithms that speed up their simulation and extend their applicability by defining new operations and subroutines for existing general circuit simulation using GSLC. To be precise:...