Lectures are given in 1.5 hour blocks (24 hours of lectures in total) and will take place in Worringer Weg 2 (Sammelbau Chemie, Melaten Campus), Room 38A2.
The school headquarters is at Physik Modulbau 2. Seminar rooms MB2 116/117 and the IQI floor in MB2 are available for students for studying (eduroam wireless access is available) and meeting in between lectures.

Lectures by D.P. DiVincenzo (3 blocks): Basics of Quantum Information, Qubits, Quantum Gates & Circuits, Theoretical Introduction to Superconducting Qubits

Lectures by H. Bluhm (3 blocks): Introduction to solid-state qubits, quantum measurement, origin and mitigation of decoherence, semiconductor quantum dot qubits

Lectures by B.Terhal (3 blocks): Quantum error correction

Lectures by F. Hassler (2 blocks): Topological quantum computing, Abelian and Non-Abelian Berry phases, Majorana fermions

Lectures by R. Renner (3 blocks): Quantum thermodynamics

Lectures by S. Wehner (2 blocks): Entropies, randomness and cryptography

Suzanne van Dam (TU Delft)
Abstract:Quantum mechanics is a well-established theory, but it still contains concepts that are the subject of foundational debate. One of these concepts is quantum contextuality, which describes the impossibility to assign an outcome to a measurement independent of which other compatible measurements are performed. In this presentation I will explain the notion of contextuality, and discuss how it can be tested experimentally. This will reveal open experimental challenges, that can inspire new experiments on quantum contextuality.

Propagating phonons coupled to an artificial atom

Maria Ekström (TU Chalmers)
Abstract: Superconducting qubits have been studied in several experiments, primarily using electromagnetic waves. We instead use mechanical vibrations in the form of propagating phonons to interact with a superconducting qubit (M. Gustafsson et al, Science (2014)). Our qubit is a transmon, fabricated on a piezoelectric material and it can interact with surface acoustic waves (SAW) in the gigahertz frequency range. An interdigital transducer (IDT) can convert electrical signals into surface acoustic waves, which we send to the transmon. The IDT can also pick up SAW phonons that the transmon emits. The speed of the surface acoustic wave is five order of magnitude slower than the speed of light and which should allow real time manipulation of quantum circuits unfeasible with photons. In addition, the strong piezoelectric coupling enables us to explore regimes of ultra strong qubit coupling difficult to reach with photonics devices.

Deterministically Preparing Code States in an Oscillator

Daniel Weigand (RWTH Aachen)
Abstract: Gottesman, Preskill and Kitaev have formulated a way of encoding a qubit into an oscillator. The scheme would offer several advantages for experiments, in that it uses simple optical components for qubit storage, error correction and fault tolerant gates, but at the cost of code states that are hard to construct. In recent years, experimental techniques were developed that may make the construction of these code states feasible.
I will give a short introduction to the code and its most important features, and present a deterministic experimental circuit-QED scheme to approximately encode a qubit in an oscillator using a transmon coupled dispersively to a microwave cavity mode. In the presented scheme, the qubit is encoded by using the transmon and displacement pulses controlled by the transmon to perform an eigenvalue estimation of the unitary stabilizers of the code.

Calibration of two superconducting qubit gates

Johannes Heinsoo (ETH Zürich)
Abstract: Rapid development of superconducting quantum circuits makes it good candidate for scalable quantum computation. While single qubit operations are considered routine, high fidelity multi qubit gates are still somewhat of a challenge. In this talk I will explain, how two qubit operations are carried out using magnetic flux pulses and resonator intermediated coupling and how one can calibrate the relevant parameters.

Overview of LecturesLectures are given in 1.5 hour blocks (24 hours of lectures in total) and will take place in Worringer Weg 2 (Sammelbau Chemie, Melaten Campus),

Room 38A2.The school headquarters is at Physik Modulbau 2. Seminar rooms MB2 116/117 and the IQI floor in MB2 are available for students for studying (eduroam wireless access is available) and meeting in between lectures.

Schedule## Monday, 23 Feb.

## Tuesday, 24 Feb.

## Wednesday, 25 Feb.

Banquet/Dinner## Thursday, 26 Feb.

## Friday, 27 Feb.

Student Presentations &Presentation Skills Workshop(Lauterbach/Terhal)

## Presentations at the Workshop:

Experimental tests of quantum contextualitySuzanne van Dam (TU Delft)Abstract:Quantum mechanics is a well-established theory, but it still contains concepts that are the subject of foundational debate. One of these concepts is quantum contextuality, which describes the impossibility to assign an outcome to a measurement independent of which other compatible measurements are performed. In this presentation I will explain the notion of contextuality, and discuss how it can be tested experimentally. This will reveal open experimental challenges, that can inspire new experiments on quantum contextuality.

Propagating phonons coupled to an artificial atomMaria Ekström (TU Chalmers)Abstract: Superconducting qubits have been studied in several experiments, primarily using electromagnetic waves. We instead use mechanical vibrations in the form of propagating phonons to interact with a superconducting qubit (M. Gustafsson et al, Science (2014)). Our qubit is a transmon, fabricated on a piezoelectric material and it can interact with surface acoustic waves (SAW) in the gigahertz frequency range. An interdigital transducer (IDT) can convert electrical signals into surface acoustic waves, which we send to the transmon. The IDT can also pick up SAW phonons that the transmon emits. The speed of the surface acoustic wave is five order of magnitude slower than the speed of light and which should allow real time manipulation of quantum circuits unfeasible with photons. In addition, the strong piezoelectric coupling enables us to explore regimes of ultra strong qubit coupling difficult to reach with photonics devices.

Deterministically Preparing Code States in an OscillatorDaniel Weigand (RWTH Aachen)Abstract: Gottesman, Preskill and Kitaev have formulated a way of encoding a qubit into an oscillator. The scheme would offer several advantages for experiments, in that it uses simple optical components for qubit storage, error correction and fault tolerant gates, but at the cost of code states that are hard to construct. In recent years, experimental techniques were developed that may make the construction of these code states feasible.

I will give a short introduction to the code and its most important features, and present a deterministic experimental circuit-QED scheme to approximately encode a qubit in an oscillator using a transmon coupled dispersively to a microwave cavity mode. In the presented scheme, the qubit is encoded by using the transmon and displacement pulses controlled by the transmon to perform an eigenvalue estimation of the unitary stabilizers of the code.

Calibration of two superconducting qubit gatesJohannes Heinsoo (ETH Zürich)Abstract: Rapid development of superconducting quantum circuits makes it good candidate for scalable quantum computation. While single qubit operations are considered routine, high fidelity multi qubit gates are still somewhat of a challenge. In this talk I will explain, how two qubit operations are carried out using magnetic flux pulses and resonator intermediated coupling and how one can calibrate the relevant parameters.