Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session AAA06: V: Topological Qubits and Quantum ThermodynamicsFocus
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Sponsoring Units: DQI Chair: Tanuj Khattar Room: Virtual Room 6 |
Wednesday, March 22, 2023 12:30PM - 1:06PM |
AAA06.00001: Quantum linear network coding for entanglement distribution in restricted architecturesNiel de Beaudrap Invited Speaker: Niel de Beaudrap In many quantum hardware platforms, qubits are stored in immobile physical subsystems. Only particular pairs of spatially nearby physical qubits may directly interact, often arranged in some more-or-less periodic structure. We may describe the locations of the qubits, and the pairs which may interact, by the nodes and edges of a graph G. This raises the question of how best to perform 'remote' two-qubit operations, i.e., between qubits which are not adjacent in the graph G. 'Routing' consists of moving data physically by interchanging the data stored at various nodes in the graph; this requires many two-qubit operations, and an amount of time scaling as the distance between the nodes in the graph. If we realise two-qubit gates by gate teleportation, this reduces the problem of remote operations to the problem of entanglement swapping in the network G, which may be performed much more efficiently with fast classical processing of the teleporation measurement outcomes. However, this may still lead to bottlenecks in the graph G as one attempts to distribute multiple entangled pairs in parallel, across paths which cross in G. In this talk, I present techniques (developed with Steven Herbert) to distribute entanglement across well-structured graphs G, applying concepts from linear network coding to avoiding the problem of crossings. |
Wednesday, March 22, 2023 1:06PM - 1:18PM |
AAA06.00002: Non-Abelian Kondo Anyons - Multiple Quantum Impurities Coupled to Multiple Chiral Edge Modes Matan Lotem, Eran Sela, Moshe Goldstein Non-abelian anyons are fractional excitations of gapped topological models believed to describe certain topological superconductors or quantum Hall states. We provide numerical evidence that they emerge as independent entities also in gapless electronic models. It is well established that coupling a single spin-1/2 impurity to k multiple fermionic channels leads to frustration and fractionalization of the impurity degrees of freedom, resulting in a fractional entropy equal to the quantum dimension of a single SU(2)k anyon. It has recently been conjectured that by utilizing chiral channels (e.g., integer quantum Hall edge states) this could be generalized to multiple impurities, leading to a decoupled non-abelian SU(2)k fusion space with an anyon for each impurity [1,2]. |
Wednesday, March 22, 2023 1:18PM - 1:30PM |
AAA06.00003: Creation operators for 2+1 non-abelian anyons Nicetu Tibau Vidal, Lucia Vilchez Estevez Topological quantum computing has been a fruitful area of research in recent times. The diagrammatic formalism of 2+1 D non-abelian anyons is the framework where topological quantum computation is formulated. |
Wednesday, March 22, 2023 1:30PM - 1:42PM |
AAA06.00004: Creating adiabatic cat states of topologically coupled quantum modes Jacquelin Luneau The simplest topological pump consists in a two level system periodically driven in time at two |
Wednesday, March 22, 2023 1:42PM - 1:54PM |
AAA06.00005: A generalized framework for the quantum Zeno and anti-Zeno effects in the strong coupling regime Ghazi Khan It is well known that repeated projective measurements can either slow down (the Zeno effect) or speed up (the anti-Zeno effect) quantum evolution. Until now, studies of these effects for a two-level system interacting with its environment have focused on repeatedly preparing the excited state via projective measurements. In this paper, we consider the repeated preparation of an arbitrary state of a two-level system that is interacting strongly with an environment of harmonic oscillators. To handle the strong interaction, we perform a polaron transformation and then use a perturbative approach to calculate the decay rates for the system. Upon calculating the decay rates, we discover that there is a transition in their qualitative behaviors as the state being repeatedly prepared continuously moves away from the excited state and toward a uniform superposition of the ground and excited states. Our results should be useful for the quantum control of a two-level system interacting with its environment. |
Wednesday, March 22, 2023 1:54PM - 2:06PM |
AAA06.00006: Resonant Generation of Schrödinger Cat States in Circuit QED Mohammad Ayyash, Xicheng Xu, Matteo Mariantoni Schrödinger cat states, superpositions of opposite phase coherent states in a resonator, are nonclassical states that have recently gained a rejuvenated interest. Typical methods use a qubit-resonator system in the dispersive regime to generate such states. Such methods depend on Kerr nonlinearities and multiphoton driving processes. However, we can do much better by using a resonant qubit-resonator system with an additional resonant classical drive on the qubit. Using this method, we can generate Schrödinger cat states in a fast and resonant manner. In this case, the average photon number of the resonator grows linearly in time. This allows for cat states with lobes that grow in time. Detrimental effects to a circuit QED implementation include resonator-drive cross-talk, detuning, decoherence and excitation leakage to the third state. In this presentation, we outline how to create a cat state using a driven qubit-resonator system, and we discuss methods to deal with detuning, cross-talk, leakage and decoherence. |
Wednesday, March 22, 2023 2:06PM - 2:18PM Author not Attending |
AAA06.00007: Machine Learning for Improved Current Density Reconstruction from NV-Diamond Magnetometry Niko Reed, Danyal Bhutto, Matthew J Turner, Sean Oliver, Kevin S Olsson, Nick Langellier, Dmitro Martynowych, Mark J Ku, Matthew S Rosen, Ronald L Walsworth Reconstructing current densities from magnetic field measurements is an important technique with applications in condensed matter, circuit design, quality control, plasma physics, and biology. Analytic reconstruction methods exist for planar currents, but break down in the presence of high spatial frequency noise or large standoff distance, restricting the types of systems that can be studied. We demonstrate a domain-transform manifold learning method that significantly exceeds the performance of analytic reconstructions for data with high noise or large standoff distances. This technique allows us to reduce the collection time of our NV-diamond magnetometer by a factor of about 400; and can also be useful in reconstructing weaker current sources. |
Wednesday, March 22, 2023 2:18PM - 2:30PM |
AAA06.00008: Anomalous temporal periodicity in the kicked top. Amit Anand, Jack Davis, Shohini Ghose Quantum-classical correspondence plays an important role in understanding the emergence of classical chaos from an underlying quantum mechanics. Here we present several families of quantum dynamics, each parameterized by dimension, that do not approach the classically chaotic dynamics as predicted by Bohr's correspondence principle. The quantum dynamics take the form of stroboscopic unitary kicks acting on a single spin system, and have the same finite temporal periodicity for all dimensions including the highly semiclassical regime. This state-independent periodicity implies that no initial quantum state fully explores Hilbert space as a state vector or phase space as a quasi-probability distribution. We also consider the stability of these families as a function of the degree of chaos in the classical model. Our study suggests that even in the semi-classical limit, there are specific parameter values for which a quantum system never behaves classically or displays signatures of chaos. |
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