“When a computer can manipulate the state efficiently, it can start doing a lot more” explained John Morton, co-founder, and CTO of Quantum Motion at the January 2023, IET Central London Network evening lecture at IET Savoy Place, hosted by Dr Mathew Davies.

He spoke about the journey of quantum computing, including how the Colossus computer first built in Dollis Hill, London, 1943 used vacuum-tubes to control electric current flow in high vacuums between electrodes. He highlighted the journey of ‘Physical Resources per Bit’ - from Mechanical and Vacuum technology that need room-size space, through to Silicon transistors, that became as small as 12mm2. He moved on to talk about the differences between classical computers vs quantum computers in terms of processing speeds from days into seconds and talked through a case study on Shor’s algorithm that explains as quantum computing power increases, so the does the ability to challenge current encryption algorithms. Where a noiseless universal quantum computer with about 4000 qubits is expected to break RSA2048.

He spoke about quantum data and the importance of amplitude and phase in qubit generation before moving onto the topic of ‘building real systems with quantum hardware’ - whether that be Superconducting qubits, Trapped ion / atom qubits and Photonic qubits. In terms of quantum hardware, he explained how depending on quantum bit error rates, some transactions can fail. To address this, industry is working to reduce error rates, though, the greater the error rate, the greater the reduncnany is required.

Interestingly, he highlighted that even though quantum computing offers new methods of processing, it does not mean we need revolution in underlying hardware – and that is where industry can start looking at silicon chips. Quantum transistors can trap single electrons then exploit their spin up and spin down to zero but requires high fidelity industrial grade fabs for the silicon qubits. He explained that measuring spin of qubits and associated variables of neighboring electron spins can give different capacitance that can be measured by radio frequency reflectometry. He reviewed ‘Pauli Spin Blockade’ in double quantum dots that provides an efficient, temperature independent mechanism for qubit readout and highlights the importance of retaining single state spins.

Alberto Gomez Saiz, IC Team Lead at Quantum Motion, took to the stage and spoke on the topic of ‘Cryo-Electronics for Quantum Computers’. He explained the role temperature plays in quantum computing, and how cooling devices down to -273 degrees Celsius is enabling new class of quantum and nanotechnology applications. He focused on quantum states dynamics and that quantum states can be changed with EM excitations and talked through actual controller architecture involved for processing semiconductor qubits, performing electric excitations into transceiver IC’s. He walked the audience through difference options for controller locations, and the importance that temperature cooling plays not only for the platform, but the changes in properties for materials. He then spoke about Quantum Motion’s latest chip, called Bloomsbury, that is a 3x3mm2 device created by a tier one foundry using the same mass production processes used in standard electronic chip manufacturing. But unlike regular computer chips, Bloomsbury contains thousands of quantum dots into which single electrons can be loaded, one by one, to serve as qubits.

This was a fascinating talk on how silicon transistors were a starting point and are now primed to become a platform for quantum computing.

Read about IET’s research on Quantum Computing as a ‘Hot Topic’ here. 
Read full details about Quantum Motion’s latest chip ‘Bloomsbury’ here.