Related Experiment Video
Updated: Jun 20, 2026
05:39
Scalable Quantum Integrated Circuits on Superconducting Two-Dimensional Electron Gas Platform
Published on: August 2, 2019
Coherent tunneling adiabatic passage with the alternating coupling scheme
L M Jong1, A D Greentree, V I Conrad
1Centre for Quantum Computer Technology, School of Physics, University of Melbourne, VIC 3010, Australia. lmjong@unimelb.edu.au
Nanotechnology
|September 10, 2009
Summary
We explored coherent tunneling adiabatic passage (CTAP) for real-space particle transport. This method enables long-range quantum transport in silicon, operating within practical timescales.
Area of Science:
- Quantum physics
- Solid-state physics
- Nanotechnology
Background:
- Adiabatic passage techniques are explored for real-space particle transport.
- Coherent tunneling adiabatic passage (CTAP) with alternating tunneling matrix elements is investigated.
Purpose of the Study:
- To investigate CTAP properties with alternating tunneling matrix elements for long-range quantum transport.
- To introduce simplified coupling protocols, transient eigenspectra, and a realistic gate design for CTAP.
Main Methods:
- Pairwise treatment of tunnel couplings for a five-donor device.
- Analysis of donor spacings (30 nm) and total chain length (120 nm).
Main Results:
- CTAP with alternating tunneling matrix elements offers a novel route for quantum transport.
- Estimated timescale for adiabatic operation is approximately 70 ns.
- This timescale is compatible with electron spin and charge relaxation times in silicon.
Conclusions:
- CTAP with alternating tunneling matrix elements is a viable method for long-range quantum transport in silicon.
- The proposed gate design and protocols facilitate practical implementation.
- The study demonstrates the potential for controlled quantum transport in nanoscale devices.
Related Concept Videos
01:18Adiabatic Processes for an Ideal Gas
When an ideal gas is compressed adiabatically, that is, without adding heat, work is done on it, and its temperature increases. In an adiabatic expansion, the gas does work, and its temperature drops. Adiabatic compressions actually occur in the cylinders of a car, where the compressions of the gas-air mixture take place so quickly that there is no time for the mixture to exchange heat with its environment. Nevertheless, because work is done on the mixture during the compression, its...
01:21Path Between Thermodynamics States
Consider the two thermodynamic processes involving an ideal gas that are represented by paths AC and ABC in Figure 1:
01:20Work Done in an Adiabatic Process
Consider the adiabatic compression of an ideal gas in the cylinder of an automobile diesel engine. The gasoline vapor is injected into the cylinder of an automobile engine when the piston is in its expanded position. The temperature, pressure, and volume of the resulting gas-air mixture are 20 °C, 1.00 x 105 N/m2, and 240 cm3 , respectively. The mixture is then compressed adiabatically to a volume of 40 cm3. Note that, in the actual operation of an automobile engine, the compression is not...
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
01:21Joule-Thomson Effect
The Joule-Thomson effect, also known as the Joule-Kelvin effect, describes the temperature change of a fluid when it is forced through a valve or porous plug while keeping it in a thermally insulated environment. This experiment is called a throttling process. This is an important effect widely used in refrigeration and the liquefaction of gases.
This experiment forces high-pressure gas through a throttle valve or a porous plug to a lower-pressure region. The gas expands as it passes through to...
This experiment forces high-pressure gas through a throttle valve or a porous plug to a lower-pressure region. The gas expands as it passes through to...
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...