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Germanium Quantum Technology

01 /What can CMOS technology do for quantum computing? 02 /Semiconductor devices and scaling with industrial approach 03 /Semiconductor foundry facilities: the good and the bad for qubits 04 /IMEC's latest qubit developments 05 /Summary and outlook 06 /Semiconductors for spin qubits 07 /Germanium quantum wells on silicon 08 /Germanium quantum wells on silicon-germanium 09 /Growth methods 10 /Characterization techniques 11 /Electrical characterization of germanium quantum wells 12 /Fabrication of H-FET 13 /Semiconductor qubits: vision and challenges 14 /Quantum materials 15 /Quantum dot qubits and their operation 16 /Types of quantum dot qubits 17 /Qubit Readout 18 /Qubit Control 19 /Qubit Coherence and Fidelity 20 /Multi-qubit control and quantum algorithms 21 /Quantum links and scaling 22 /Physics of holes 23 /Hole spin qubits 24 /Introduction to electronics for quantum computing 25 /Room temperature electronics 26 /Cryogenic qubit chip carriers 27 /Contribution to IGNITE 28 /Quantum Control Stack for Spin Qubits 29 /Auto-tuning a quantum computer 30 /Tuning and operation of arrays 31 /Finding operation points example 32 /What is auto-tuning? 33 /Neural network tuning 34 /Navigating charge stability diagrams 35 /Experimental implementation 36 /Towards universal quantum algorithms 37 /Classical error correction 38 /Quantum error correction 39 /Progress and challenges 40 /Introduction to quantum algorithms 41 /The first algorithms 42 /Quantum annealing 43 /Quantum Machine Learning

Quantum dot qubits and their operation

In this video, Menno Veldhorst will present operations with quantum dots, in particular with strained germanium. 

Prerequisite knowledge

  • Quantum dots in solid-state physics  
  • Strained heterostructures 

Main takeaways

  • Larger quantum dot arrays require a uniform electrostatic landscape in order to implement crossbar architecture for example in decreasing of number of gates.  
  • Hysteresis tuning enables to change the potential landscape of the device  
  • Quantum dots array can also be implemented in a double quantum well heterostructure for higher qubit connectivity 

Further thinking

True or False: When tuning a quantum dots array, it possible to apply the same gate voltage on every dot to reach the single charge regime.

Solution

Further reading

4x4 quantum dot array: https://arxiv.org/abs/2209.06609 
Hysteresis tuning of quantum dots: https://arxiv.org/pdf/2211.13493.pdf 
https://arxiv.org/abs/2309.03591 
Double quantum well structure: https://arxiv.org/abs/2305.14064 
Loss and DiVicenzo quantum dots computation proposal: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.57.120