Periodic Reporting for period 2 - UltraFastNano (Electronic generation and detection in nanoelectronic devices at the picosecond scale)
Reporting period: 2021-01-01 to 2022-12-31
Quantum Technology is an emerging new and radically different information technology. Its advocates foresee it as a future large industry, with a potential impact of a similar scale to conventional IT and of key importance for the digital single market and for industry and growth. Presently huge investments are being made world-wide to consolidate this new technology.
Most quantum technologies under development focus on localized quantum states such as superconducting circuits or the electron spin of an electron trapped by electrostatic confinement. In contrast, quantum nanoelectronics studied in this project aims at manipulating propagating quantum states, at increasingly high frequencies beyond the 10 GHz range. In this regime, elementary excitations are either electronic or photon like, with potential applications that span quantum technologies (communications between quantum devices, sensing, quantum computation) and fundamental scientific problems. Addressing frequencies beyond this range, in the THz regime, is extremely difficult for electronic devices. Prior to this project, this kind of time scale could only be accessed by optical methods, and was not possible electrically. The goal of UltraFastNano is to develop the first quantum nanoelectronics platform operating at picosecond time scales.
To give an example, the coherence of quantum devices such as semiconductor qubits is naturally short lived and require ultrafast operation speed in order to increase the number of possible quantum operations. A key quantity used to characterise the performance of a quantum device is the ratio between two characteristic times: the time a qubit can survive its quantum properties and the time it takes to complete its operation. With UltraFastNano we will push the limit of operation speed for quantum nanoelectronic devices to timescales down to 1 picosecond.
The UltraFastNano project will pioneer new concepts at the crossroads between quantum optics and solid-state nanoelectronics. Its aim is to achieve full control of quantum excitations that propagate through the quantum devices on the picosecond scale, about three orders of magnitude faster than other quantum technologies. The main objectives include
• Picosecond on-demand coherent single-particle source
• Single-shot detection of propagating excitations at the discrete charge level
• Quantum interferometry at the single-charge level
• New software for predictive simulation and optimisation of ultrafast quantum devices
Most quantum technologies under development focus on localized quantum states such as superconducting circuits or the electron spin of an electron trapped by electrostatic confinement. In contrast, quantum nanoelectronics studied in this project aims at manipulating propagating quantum states, at increasingly high frequencies beyond the 10 GHz range. In this regime, elementary excitations are either electronic or photon like, with potential applications that span quantum technologies (communications between quantum devices, sensing, quantum computation) and fundamental scientific problems. Addressing frequencies beyond this range, in the THz regime, is extremely difficult for electronic devices. Prior to this project, this kind of time scale could only be accessed by optical methods, and was not possible electrically. The goal of UltraFastNano is to develop the first quantum nanoelectronics platform operating at picosecond time scales.
To give an example, the coherence of quantum devices such as semiconductor qubits is naturally short lived and require ultrafast operation speed in order to increase the number of possible quantum operations. A key quantity used to characterise the performance of a quantum device is the ratio between two characteristic times: the time a qubit can survive its quantum properties and the time it takes to complete its operation. With UltraFastNano we will push the limit of operation speed for quantum nanoelectronic devices to timescales down to 1 picosecond.
The UltraFastNano project will pioneer new concepts at the crossroads between quantum optics and solid-state nanoelectronics. Its aim is to achieve full control of quantum excitations that propagate through the quantum devices on the picosecond scale, about three orders of magnitude faster than other quantum technologies. The main objectives include
• Picosecond on-demand coherent single-particle source
• Single-shot detection of propagating excitations at the discrete charge level
• Quantum interferometry at the single-charge level
• New software for predictive simulation and optimisation of ultrafast quantum devices
RP1 was described in the previous report
RP2:
In the UltraFastNano project's second and third years, we made progress in all work packages. We developed voltage pulse generators using two approaches: A) a frequency comb-based generator producing stable 20 ps pulses and single-electron wave packets with a 27 ps duration; B) an optoelectronic conversion-based generator producing ultrafast voltage pulses up to 2.3ps. We also developed a sensitive single-electron charge detector and demonstrated electron-photon interface. Additionally, we performed first quantum interference experiments using voltage pulses and developed a dynamic two-particle interferometry suitable for quantifying the quantum coherence of a fractional quantum Hall channel. Finally, we made important progress in the realistic electrostatic modeling of GaAs-based nanoelectronic devices.
Achievements:
Several important results of reporting period 2 were achieved:
- A novel voltage generator based on a frequency comb was developed. With this novel generator, we succeeded in generating and detecting an electron wave packet with a temporal duration of 27 ps - the shortest reported so far.
- The newly developed technique of ultrafast pulsing was applied to the generation of acoustic pulses.
- A novel dynamic two-particle interferometry has been developed that is suitable for quantifying the quantum coherence of a fractional quantum Hall channel.
RP2:
In the UltraFastNano project's second and third years, we made progress in all work packages. We developed voltage pulse generators using two approaches: A) a frequency comb-based generator producing stable 20 ps pulses and single-electron wave packets with a 27 ps duration; B) an optoelectronic conversion-based generator producing ultrafast voltage pulses up to 2.3ps. We also developed a sensitive single-electron charge detector and demonstrated electron-photon interface. Additionally, we performed first quantum interference experiments using voltage pulses and developed a dynamic two-particle interferometry suitable for quantifying the quantum coherence of a fractional quantum Hall channel. Finally, we made important progress in the realistic electrostatic modeling of GaAs-based nanoelectronic devices.
Achievements:
Several important results of reporting period 2 were achieved:
- A novel voltage generator based on a frequency comb was developed. With this novel generator, we succeeded in generating and detecting an electron wave packet with a temporal duration of 27 ps - the shortest reported so far.
- The newly developed technique of ultrafast pulsing was applied to the generation of acoustic pulses.
- A novel dynamic two-particle interferometry has been developed that is suitable for quantifying the quantum coherence of a fractional quantum Hall channel.
The long-term vision of UltraFastNano includes the much-needed quantum bus allowing direct interaction between distant quantum bits, hence a drastic reduction of the hardware footprint for quantum error correction protocols. It also includes the possibility of more disruptive quantum technologies such as flying qubit architectures, a radically different route from the mainstream semiconducting or super-conducting approach followed by the major nanoelectronic companies (Google, IBM, Intel, etc.).
UltraFastNano aims to achieve these goals be fighting decoherence with a dramatic increase of operation speed. In the long-term, pushing towards this frequency range will enable quantum technologies that operate without the need of a cryogenic environment (6 THz 300K).
The three technological milestones of UltraFastNano – (i) 1 ps single-electron source, (ii) single-electron detection and (iii) optoelectronic interface – have important potential for triggering disruptive innovation on ultrafast electronics for (cryogenic) THz voltage source or detection. This novel and efficient method for generating ultrafast pulses can find numerous applications for on-chip THz spectroscopy and for THz wireless communications. UltraFastNano will also find immediate applications for metrologically-accurate measurements of the ampere and picosecond optoelectronic devices that convert between electronic and photonic excitations.
In addition, the simulation tools developed within the UltraFastNano project will be directly integrated into nextnano commercial products/software. The implemented features will increase the capabilities of the nextnano software in simulating a large range of nanoelectronic devices such as silicon nanowire transistors or silicon spin qubits.
UltraFastNano aims to achieve these goals be fighting decoherence with a dramatic increase of operation speed. In the long-term, pushing towards this frequency range will enable quantum technologies that operate without the need of a cryogenic environment (6 THz 300K).
The three technological milestones of UltraFastNano – (i) 1 ps single-electron source, (ii) single-electron detection and (iii) optoelectronic interface – have important potential for triggering disruptive innovation on ultrafast electronics for (cryogenic) THz voltage source or detection. This novel and efficient method for generating ultrafast pulses can find numerous applications for on-chip THz spectroscopy and for THz wireless communications. UltraFastNano will also find immediate applications for metrologically-accurate measurements of the ampere and picosecond optoelectronic devices that convert between electronic and photonic excitations.
In addition, the simulation tools developed within the UltraFastNano project will be directly integrated into nextnano commercial products/software. The implemented features will increase the capabilities of the nextnano software in simulating a large range of nanoelectronic devices such as silicon nanowire transistors or silicon spin qubits.