Qubits built out of Majorana zero modes constitute the primary path toward topologically protected quantum computing. Simulating the braiding process of multiple Majorana zero modes corresponds to the quantum dynamics of a superconducting many-body system. It is crucial to study the Majorana dynamics both in the presence of all other quasiparticles and for reasonably large system sizes. We present a method to calculate arbitrary many-body wave functions as well as their expectation values, correlators, and overlaps from time evolved single-particle states of a superconductor, allowing for significantly larger system sizes. We calculate the fidelity, transition probabilities, and joint parities of Majorana pairs to track the quality of the braiding process. We show how the braiding success depends on the speed of the braid. Moreover, we demonstrate the topological CNOT two-qubit gate as an example of two-qubit entanglement. Our Letter opens the path to test and analyze the many theoretical implementations of Majorana qubits. Moreover, this method can be used to study the dynamics of any noninteracting superconductor.
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http://dx.doi.org/10.1103/PhysRevLett.131.176601 | DOI Listing |
Phys Rev Lett
December 2024
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China.
By braiding non-Abelian anyons it is possible to realize fault-tolerant quantum algorithms through the computation of Jones polynomials. So far, this has been an experimentally formidable task. In this Letter, a photonic quantum system employing two-photon correlations and nondissipative imaginary-time evolution is utilized to simulate two inequivalent braiding operations of Majorana zero modes.
View Article and Find Full Text PDFMaterials (Basel)
December 2024
Computational Nanoelectronics Group, University of Zagreb Faculty of Electrical Engineering and Computing, HR 10000 Zagreb, Croatia.
The problems of disorder and insufficient system length are generally regarded as central problems in the realization of Majorana zero modes (MZM), which are a promising platform for realizing fault-tolerant topological quantum computing (TQC). In this work, we analyze eigenenergy spectra and transport properties of finite Kitaev chains using quantum transport simulations in a wide design space of hopping amplitude (), superconductor pairing (Δ), and electrochemical potential. Our goal is to determine critical or minimum acceptable chain lengths to obtain oscillation-free MZMs with suitable microsecond coherence times, and observable zero-bias conductance peaks (ZBCP) quantized almost at ~2/.
View Article and Find Full Text PDFACS Nano
December 2024
School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Realizing Majorana Fermions has always been regarded as a crucial and formidable task in topological superconductors. In this work, we report a physical mechanism and a material platform for realizing Majorana zero modes (MZMs). This material platform consists of open circular helix molecule (CHM) proximity coupled with an -wave superconductor (under an external magnetic field) or interconnected-CHM chain coupled with a phase-bias -wave superconducting heterostructure (without any external magnetic field).
View Article and Find Full Text PDFNat Commun
November 2024
School of Emerging Technology and Department of Physics, University of Science and Technology of China, Hefei, 230026, China.
The hybrid ferromagnet-superconductor heterostructures have attracted extensive attention as they potentially host topological superconductivity. Relevant experimental signatures have recently been reported in CrBr/NbSe ferromagnet-superconductor heterostructure, but controversies remain. Here, we reinvestigate CrBr/NbSe by an ultralow temperature scanning tunneling microscope with higher spatial and energy resolutions.
View Article and Find Full Text PDFJ Phys Condens Matter
November 2024
Institute of Physics, M. Curie-Skłodowska University, 20-031 Lublin, Poland.
We study the quasiparticle spectrum of a hybrid system, comprising a correlated (Anderson-type) quantum dot coupled to a topological superconducting nanowire hosting the Majorana boundary modes. From the exact solution of the low-energy effective Hamiltonian, we uncover a subtle interplay between Coulomb repulsion and the Majorana mode. Our analytical expressions show that the spectral weight of the leaking Majorana mode is sensitive to both the quantum dot energy level and the repulsive potential.
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