Abstract
The theory of quantum information provides a common language which links disciplines ranging from cosmology to condensed-matter physics. For example, the delocalization of quantum information in strongly-interacting many-body systems, known as quantum information scrambling, has recently begun to unite our understanding of black hole dynamics, transport in exotic non-Fermi liquids, and many-body analogs of quantum chaos. To date, verified experimental implementations of scrambling have dealt only with systems comprised of two-level qubits. Higher-dimensional quantum systems, however, may exhibit different scrambling modalities and are predicted to saturate conjectured speed limits on the rate of quantum information scrambling. We take the first steps toward accessing such phenomena, by realizing a quantum processor based on superconducting qutrits (three-level quantum systems). We implement two-qutrit scrambling operations and embed them in a five-qutrit teleportation algorithm to directly measure the associated out of-time-ordered correlation functions. Measured teleportation fidelities, Favg = 0.568 +- 0001, confirm the occurrence of scrambling even in the presence of experimental imperfections. Our teleportation algorithm, which connects to recent proposals for studying traversable wormholes in the laboratory, demonstrates how quantum information processing technology based on higher dimensional systems can exploit a larger and more connected state space to achieve the resource efficient encoding of complex quantum circuits.
Highlights
We demonstrate the implementation of universal two-qutrit scrambling operations and embed them in a five-qutrit quantum teleportation protocol
While the majority of current generation quantum processors are based on qubits, qutrit-based systems have long been known to exhibit significant advantages in the context of quantum technology: They have been touted for their small code sizes in the context of quantum error correction [2], high-fidelity magic state distillation [3], and more robust quantum cryptography protocols [4,5]
We have demonstrated a five-qutrit quantum processor built from superconducting transmon circuits
Summary
While the majority of current generation quantum processors are based on qubits, qutrit-based (and, more generally, qudit-based [1]) systems have long been known to exhibit significant advantages in the context of quantum technology: They have been touted for their small code sizes in the context of quantum error correction [2], high-fidelity magic state distillation [3], and more robust quantum cryptography protocols [4,5]. A quantum processor can, in principle, directly measure the scrambling-induced spread of initially localized information via the decay of so-called out-oftime-ordered correlation functions (OTOCs) [13,16,17,18,19,20,21,22,23] This capability was recently demonstrated in a qubit-based system, using a seven-qubit teleportation algorithm analogous to the five-qutrit protocol we implement in this work [24,25,26]. The superconducting qutrit processor we develop here features long coherence times; multiplexed readout of individual qutrits; fast, high-fidelity single-qutrit operations; and two types of two-qutrit gates for generating entanglement Using this gate set on our processor, we construct a maximally scrambling qutrit unitary and characterize it using quantum process tomography. While we choose quantum scrambling as a demonstration of our processor, our work opens the door more broadly to the experimental study of quantum information processing utilizing qutritbased logic
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
