Related Experiment Video
Updated: Jul 6, 2025
10:00
Gradient Echo Quantum Memory in Warm Atomic Vapor
Published on: November 11, 2013
12.9K
Initial State Encoding via Reverse Quantum Annealing and H-Gain Features
Elijah Pelofske1, Georg Hahn2, Hristo Djidjev1,3
1CCS-3 Information Sciences, Los Alamos National Laboratory, Los Alamos, NM 87545 USA.
IEEE Transactions on Quantum Engineering
|January 5, 2024
Summary
This study explores reverse annealing (RA) and h-gain (HG) features on D-Wave quantum annealers to improve optimization solutions. The h-gain technique offers a viable alternative to reverse annealing for certain problems.
Area of Science:
- Quantum Computing
- Computational Optimization
Background:
- D-Wave quantum annealers offer cloud access to quantum annealing for optimization.
- Improving solution quality in quantum annealing is an active research area.
Purpose of the Study:
- To investigate methods for enhancing quantum annealer solution quality by encoding initial states.
- To compare the effectiveness of reverse annealing (RA) and h-gain (HG) features for initial state encoding.
Main Methods:
- Exploration of D-Wave's reverse annealing (RA) feature for refining solutions.
- Utilizing the h-gain (HG) feature to bias annealing from a specific initial state.
- Development and testing of a hybrid RA-HG method and iterative application of both techniques.
- Evaluation on combinatorial optimization problems like max-cut and max-clique, and on spin glasses using D-Wave hardware.
Main Results:
- The h-gain (HG) feature is demonstrated as a viable alternative to RA for initial state encoding in quantum annealing.
- Iterative application of RA and HG shows potential for monotonically improving solutions.
- Performance of iterative RA and HG is analyzed on various problems and D-Wave hardware architectures (Chimera, Pegasus).
Conclusions:
- Both RA and HG are effective for initial state encoding in quantum annealing.
- Iterative application of these techniques can lead to progressively better solutions.
- HG presents a promising alternative or complement to RA for optimizing problem-solving on quantum annealers.
Related Concept Videos
03:24Hybridization of Atomic Orbitals I
47.1K
The mathematical expression known as the wave function, ψ, contains information about each orbital and the wavelike properties of electrons in an isolated atom. When atoms are bound together in a molecule, the wave functions combine to produce new mathematical descriptions that have different shapes. This process of combining the wave functions for atomic orbitals is called hybridization and is mathematically accomplished by the linear combination of atomic orbitals. The new orbitals that...
47.1K
01:23Atomic Nuclei: Nuclear Relaxation Processes
656
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
656
03:35Hybridization of Atomic Orbitals II
32.3K
sp3d and sp3d 2 Hybridization
32.3K
01:15Gain
181
Gain and phase shift are properties of linear circuits that describe the effect a circuit has on a sinusoidal input voltage or current. The circuit's behavior that contains reactive elements will depend on the frequency of the input sinusoid. As a result, it is observed that the gain and phase shift will all be frequency functions.
Gain:
Suppose Vin is the input and Vout is the output signal to a circuit.
Gain:
Suppose Vin is the input and Vout is the output signal to a circuit.
181
01:27State Space Representation
209
The frequency-domain technique, commonly used in analyzing and designing feedback control systems, is effective for linear, time-invariant systems. However, it falls short when dealing with nonlinear, time-varying, and multiple-input multiple-output systems. The time-domain or state-space approach addresses these limitations by utilizing state variables to construct simultaneous, first-order differential equations, known as state equations, for an nth-order system.
Consider an RLC circuit, a...
Consider an RLC circuit, a...
209
01:03Atomic Nuclei: Nuclear Spin State Overview
958
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of...
958