Majorana fermions are particles that could potentially be used as information units for a quantum computer. An experiment by physicists at the Swiss Nanoscience Institute and the University of Basel’s Department of Physics has confirmed their theory that Majorana fermions can be generated and measured on a superconductor at the end of wires made from single iron atoms. The researchers also succeeded in observing the wave properties of Majoranas and, therefore, in making the interior of a Majorana visible for the first time. The results were published in the Nature journal npj Quantum Information.
Around 75 years ago, Italian physicist Ettore Majorana hypothesized the existence of exotic particles that are their own antiparticles. Since then, interest in these particles, known as Majorana fermions, has grown enormously given that they could play a role in creating a quantum computer.
Majoranas have already been described very well in theory. However, examining them and obtaining experimental evidence is difficult because they have to occur in pairs but are then usually bound to form one normal electron. Ingenious combinations and arrangements of various materials are therefore required to generate two Majoranas and keep them apart.
Collaboration between theory and practice
The group led by Professor Ernst Meyer has now used predictions and calculations by theoretical physicists Professor Jelena Klinovaja and Professor Daniel Loss (from the Swiss Nanoscience Institute and the University of Basel’s Department of Physics) to experimentally measure states that correspond to Majoranas.
On a superconductor, the researchers evaporated single iron atoms with spin that, due to the row structure of the lead atoms, arrange themselves into a minute wire comprising one row of single atoms. The wires reached an astounding length of up to 70 nanometers.
Single Majoranas on the ends
The researchers examined these mono-atomic chains with the aid of scanning tunneling microscopy and, for the first time, with an atomic force microscope as well. Using the images and measurements, they found clear indications of the existence of single Majorana fermions on the ends of the wires under certain conditions and from a specific wire length on.
Despite the distance between them, the two Majoranas on the ends of the wires are still connected. Together, they form a new state extended across the whole wire that can either be occupied (“1”) or not occupied (“0”) by an electron. This binary property can then serve as the basis for a quantum bit (Qubit) and means that Majoranas, which are also very robust against a number of environmental influences, are promising candidates for creating a future quantum computer.
Predicted wavefunction measured
The researchers from Basel have not only shown that single Majoranas can be generated and measured at the ends of an iron wire, they also performed the first experiment to show that Majoranas are extended quantum objects with an inner structure, as predicted by their theory colleagues. Over an area of several nanometers, the measurements showed the expected wavefunction with characteristic oscillations and twofold decay lengths, which have now been made visible for the first time.
Rémy Pawlak, Marcin Kisiel, Jelena Klinovaja, Tobias Meier, Shigeki Kawai, Thilo Glatzel, Daniel Loss, and Ernst Meyer
Probing atomic structure and Majorana wavefunctions in mono-atomic Fe chains on superconducting Pb surface
npj Quantum Information (2016), doi: 10.1038/npjqi.2016.35
Prof. Dr. Jelena Klinovaja, University of Basel, Department of Physics, tel +41 61 267 36 56, email: firstname.lastname@example.org
Prof. Dr. Daniel Loss, University of Basel, Department of Physics, tel +41 61 267 37 49, email: email@example.com
Prof. Dr. Ernst Meyer, Univeristy of Basel, Department of Physics, tel +41 61 267 37 24, email:firstname.lastname@example.org
Reto Caluori | Universität Basel
Structured light and nanomaterials open new ways to tailor light at the nanoscale
23.04.2018 | Academy of Finland
On the shape of the 'petal' for the dissipation curve
23.04.2018 | Lobachevsky University
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
23.04.2018 | Physics and Astronomy
23.04.2018 | Physics and Astronomy
23.04.2018 | Trade Fair News