Scientists are constantly searching for ways to improve quantum computers, devices that use the principles of quantum physics to process information and solve problems that traditional computers cannot. One of the main challenges facing quantum computers is the preservation of quantum data for an extended period of time, known as the time of coherence. This determines how long a cube, the essential component of a quantum computer, can remain in a superposition of two states, 0 and 1.
Recent research from various organizations such as the Center for Functional Nanomaterials and the National Synchrotron Source of the Light II, finds that tantalum, a superconducting metal with a high melting point and excellent resistance to corrosion, is a promising material for creating cubes with longer coherence times. Specifically, cubes made of tantalum can maintain quantum information for more than half a billion seconds, five times longer than cubes made of other metals.
To understand why tantalum works so well, scientists turned to X-ray photoelectronic spectroscopy, a method of determining the composition and thickness of the tantalum oxide layer that forms on the surface of the cubes. They discovered that this layer is heterogeneous and contains different forms of tantalum oxide with varying electronic structures and coherence. They also found that the thickness of the tantalum oxide layer depends on how it is formed – in the air or in a vacuum.
Researchers suggest that the heterogeneity of the tantalum oxide layer creates local electric fields that may interfere with the quantum state of the cubes. Some forms of tantalum oxide may also be superconducting and reduce energy losses in the cubes. Scientists hope that understanding these properties of tantalum will lead to better methods of modifying its surface and creating a more homogeneous and optimal tantalum oxide layer. These advancements could lead to more powerful and reliable quantum computers in the future.