Related Experiment Video
Updated: May 11, 2026
16:11
Implementation of a Reference Interferometer for Nanodetection
Published on: April 26, 2014
Cavity-mediated entanglement generation via Landau-Zener interferometry
C M Quintana1, K D Petersson, L W McFaul
1Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
Physical Review Letters
|May 18, 2013
Summary
Researchers achieved quantum control and entanglement using a superconducting cavity beam splitter. This method directly tests quantum transition formulas and generates entangled Bell states with 78% fidelity.
Area of Science:
- Quantum physics
- Superconducting circuits
- Quantum information science
Background:
- Superconducting circuits are a leading platform for quantum computing.
- Controlling quantum states and generating entanglement are crucial for quantum information processing.
- Landau-Zener transitions offer a mechanism for manipulating quantum systems.
Purpose of the Study:
- To demonstrate quantum control and entanglement generation using a novel Landau-Zener beam splitter.
- To experimentally verify the Landau-Zener transition formula in a coupled qubit system.
- To explore the generation of entangled states via cavity-mediated qubit-qubit interactions.
Main Methods:
- Coupling two transmon qubits to a superconducting cavity to form a Landau-Zener beam splitter.
- Performing single and consecutive sweeps through the qubit-qubit avoided crossing.
- Utilizing two-qubit state tomography to characterize the generated quantum states.
Main Results:
- Direct experimental test of the Landau-Zener transition formula.
- Observation of Landau-Zener-Stückelberg interference patterns with tunable visibility.
- Generation of a Bell state with 78% fidelity via a single passage, limited by qubit relaxation.
Conclusions:
- The demonstrated Landau-Zener beam splitter is an effective tool for quantum control and entanglement generation.
- The experimental results align with theoretical predictions of Landau-Zener transitions.
- Further improvements in qubit coherence are needed to enhance the fidelity of generated entangled states.
Related Concept Videos
01:28Standing Waves in a Cavity
A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:
01:22Carrier Generation and Recombination
Carrier generation is the process by which electron-hole pairs (EHPs) are created within the semiconductor. In direct-bandgap semiconductors, such as gallium arsenide (GaAs), this occurs efficiently when energy absorption prompts valence electrons to leap into the conduction band, leaving behind holes.
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
01:28Induced Electric Dipoles
A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...