Measurement-driven navigation in many-body Hilbert space: Active-decision steering

• URL: http://arxiv.org/abs/2111.09306v3
• Date: Fri, 21 Oct 2022 13:09:24 GMT
• Title: Measurement-driven navigation in many-body Hilbert space: Active-decision steering
• Authors: Yaroslav Herasymenko, Igor Gornyi, Yuval Gefen
• Abstract summary: In this work, we consider such active measurement-driven steering as applied to the challenging case of many-body quantum systems. For helpful decision-making strategies, we offer Hilbert-space-orientation techniques, comparable to those used in navigation.
• Score: 0.0
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The challenge of preparing a system in a designated state spans diverse facets of quantum mechanics. To complete this task of steering quantum states, one can employ quantum control through a sequence of generalized measurements which direct the system towards the target state. In an active version of this protocol, the obtained measurement readouts are used to adjust the protocol on-the-go. This enables a sped-up performance relative to the passive version of the protocol, where no active adjustments are included. In this work, we consider such active measurement-driven steering as applied to the challenging case of many-body quantum systems. For helpful decision-making strategies, we offer Hilbert-space-orientation techniques, comparable to those used in navigation. The first one is to tie the active-decision protocol to the greedy accumulation of the cost function, such as the target state fidelity. We show the potential of a significant speedup, employing this greedy approach to a broad family of Matrix Product State targets. For system sizes considered here, an average value of the speedup factor $f$ across this family settles about $20$, for some targets even reaching a few thousands. We also identify a subclass of Matrix Product State targets, for which the value of $f$ increases with system size. In addition to the greedy approach, the second wayfinding technique is to map out the available measurement actions onto a Quantum State Machine. A decision-making protocol can be based on such a representation, using semiclassical heuristics. This State Machine-based approach can be applied to a more restricted set of targets, sometimes offering advantages over the cost function-based method. We give an example of a W-state preparation which is accelerated with this method by $f\simeq3.5$, outperforming the greedy protocol for this target.

Related papers

• Deterministic Ans\"atze for the Measurement-based Variational Quantum Eigensolver [0.0]
  This study introduces MBVQE-ans"atze that respect determinism and resemble the widely used problem-agnostic hardware-efficient VQE ansatz. We find that ensuring determinism works better via postselection than by adaptive measurements at the expense of increased sampling cost. We propose an efficient MBQC-inspired method to prepare the resource state, specifically the cluster state, on hardware with heavy-hex connectivity.
  arXiv  Detail & Related papers  (2023-12-20T18:08:25Z)
• Engineering unsteerable quantum states with active feedback [0.5892638927736115]
  We propose active steering protocols for quantum state preparation in quantum circuits. We show that the standard fidelity does not give a useful cost function; instead, successful steering is achieved by including local fidelity terms. numerical simulations suggest that the active steering protocol can reach arbitrarily designated target states.
  arXiv  Detail & Related papers  (2023-08-01T09:01:51Z)
• A Quantum Optimal Control Problem with State Constrained Preserving Coherence [68.8204255655161]
  We consider a three-level $Lambda$-type atom subjected to Markovian decoherence characterized by non-unital decoherence channels. We formulate the quantum optimal control problem with state constraints where the decoherence level remains within a pre-defined bound.
  arXiv  Detail & Related papers  (2022-03-24T21:31:34Z)
• Efficient Bipartite Entanglement Detection Scheme with a Quantum Adversarial Solver [89.80359585967642]
  Proposal reformulates the bipartite entanglement detection as a two-player zero-sum game completed by parameterized quantum circuits. We experimentally implement our protocol on a linear optical network and exhibit its effectiveness to accomplish the bipartite entanglement detection for 5-qubit quantum pure states and 2-qubit quantum mixed states.
  arXiv  Detail & Related papers  (2022-03-15T09:46:45Z)
• Dynamical learning of a photonics quantum-state engineering process [48.7576911714538]
  Experimentally engineering high-dimensional quantum states is a crucial task for several quantum information protocols. We implement an automated adaptive optimization protocol to engineer photonic Orbital Angular Momentum (OAM) states. This approach represents a powerful tool for automated optimizations of noisy experimental tasks for quantum information protocols and technologies.
  arXiv  Detail & Related papers  (2022-01-14T19:24:31Z)
• Feedback-assisted quantum search by continuous-time quantum walks [58.720142291102135]
  We address the quantum search of a target node on a cycle graph by means of a quantum walk assisted by continuous measurement and feedback. In particular, our protocol is able to drive the walker to a desired target node.
  arXiv  Detail & Related papers  (2022-01-12T16:59:53Z)
• Adaptive Multi-Goal Exploration [118.40427257364729]
  We show how AdaGoal can be used to tackle the objective of learning an $epsilon$-optimal goal-conditioned policy. AdaGoal is anchored in the high-level algorithmic structure of existing methods for goal-conditioned deep reinforcement learning.
  arXiv  Detail & Related papers  (2021-11-23T17:59:50Z)
• Optimized Steering: Quantum State Engineering and Exceptional Points [1.4174475093445233]
  We analyze the steering of a two-level system using the interplay of a system Hamiltonian and weak measurements. We show that the optimization of such a steering protocol is underlain by the presence of Liouvillian exceptional points.
  arXiv  Detail & Related papers  (2021-01-18T19:02:05Z)
• Preparation of excited states for nuclear dynamics on a quantum computer [117.44028458220427]
  We study two different methods to prepare excited states on a quantum computer. We benchmark these techniques on emulated and real quantum devices. These findings show that quantum techniques designed to achieve good scaling on fault tolerant devices might also provide practical benefits on devices with limited connectivity and gate fidelity.
  arXiv  Detail & Related papers  (2020-09-28T17:21:25Z)
• Estimation of pure states using three measurement bases [0.0]
  We introduce a new method to estimate unknown pure $d$-dimensional quantum states using the probability distributions associated with only three measurement bases. The viability of the protocol is experimentally demonstrated using two different and complementary high-dimensional quantum information platforms.
  arXiv  Detail & Related papers  (2020-06-05T03:28:51Z)
• Towards the standardization of quantum state verification using optimal strategies [9.565853956571603]
  We experimentally realize the recently proposed two-qubit entangled state verification strategies. About 3283/536 number of copies ($N$) are required to verify the target quantum state for nonadaptive/adaptive strategies.
  arXiv  Detail & Related papers  (2020-02-03T10:38:15Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.