Scientists discover new way to create fault-tolerant qubits

Quantum computing has the potential to revolutionize our world by offering exponentially faster computation than traditional binary technology. However, a major challenge in developing quantum computers lies in building a stable network of qubits, which are susceptible to external disturbances. Scientists and engineers at the University of Washington have made a significant breakthrough in this area.

In their recent papers published in Nature and Science, the research team reported the detection of “fractional quantum anomalous Hall” (FQAH) states in experiments with atomically thin semiconductor materials. These FQAH states can host anyons, which are peculiar “quasiparticles” with only a fraction of an electron’s charge. Certain types of anyons can be used to create “topologically protected” qubits that are stable against local disturbances.

The FQAH states discovered by the team are related to the fractional quantum Hall state, an exotic phase of matter found in two-dimensional systems. Unlike traditional fractional quantum Hall systems that require strong magnetic fields for stability, the FQAH state remains stable even at zero magnetic field. To achieve this, the researchers built an artificial lattice by stacking two atomically thin flakes of a semiconductor material called molybdenum ditelluride (MoTe2) at small twist angles, creating a synthetic honeycomb lattice.

By cooling the stacked slices to extremely low temperatures, the system exhibited intrinsic magnetism without the need for an external magnetic field. Using lasers as probes, the researchers detected signatures of the FQAH effect, a crucial step in harnessing the power of anyons for quantum computing.

The team envisions their system as a powerful platform for studying anyons and their unique properties, which differ from those of regular particles like electrons. In future work, they aim to discover an even more exotic version of anyons known as “non-Abelian” anyons. These non-Abelian anyons could serve as topological qubits, where quantum information is spread out over the entire system and resistant to local disturbances. Such a topological qubit would be fundamentally different and more robust than current quantum computing platforms.

The researchers identified three key properties that allowed the emergence of FQAH states in their experimental setup: magnetism, topology, and strong interactions between charges. These properties together create a fertile ground for investigating and manipulating FQAH states, accelerating progress in quantum computing.

The team’s work provides exciting evidence of FQAH states and opens up possibilities for further exploration and the development of new devices for quantum applications. They are currently conducting electrical transport measurements to provide direct evidence of fractional excitations at zero magnetic field, which would solidify their findings.

Source: University of Washington

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