Virtual quantum broadcasting

• URL: http://arxiv.org/abs/2310.13049v1
• Date: Thu, 19 Oct 2023 18:00:01 GMT
• Title: Virtual quantum broadcasting
• Authors: Arthur J. Parzygnat, James Fullwood, Francesco Buscemi, Giulio Chiribella
• Abstract summary: We show that, although quantum broadcasting cannot be achieved by any physical process, it can be achieved by a virtual process. We show that the optimal physical approximation to the canonical broadcasting map is the optimal universal quantum cloning.
• Score: 2.3895981099137535
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: The quantum no-broadcasting theorem states that it is impossible to produce perfect copies of an arbitrary quantum state, even if the copies are allowed to be correlated. Here we show that, although quantum broadcasting cannot be achieved by any physical process, it can be achieved by a virtual process, described by a Hermitian-preserving trace-preserving map. This virtual process is canonical: it is the only map that broadcasts all quantum states, is covariant under unitary evolution, is invariant under permutations of the copies, and reduces to the classical broadcasting map when subjected to decoherence. We show that the optimal physical approximation to the canonical broadcasting map is the optimal universal quantum cloning, and we also show that virtual broadcasting can be achieved by a virtual measure-and-prepare protocol, where a virtual measurement is performed, and, depending on the outcomes, two copies of a virtual quantum state are generated. Finally, we use canonical virtual broadcasting to prove a uniqueness result for quantum states over time.

Related papers

• Experimental Virtual Quantum Broadcasting [1.2050877805909537]
  We develop a quantum circuit integrated with a post-processing protocol to implement virtual quantum broadcasting. We experimentally verify the closest physical map, known as the optimal quantum cloner, to the virtual broadcasting map. We identify the difference in statistical outcomes between the input of the optimal quantum cloner and its local output as the fundamental error imposed by quantum mechanics.
  arXiv  Detail & Related papers  (2025-01-20T10:33:35Z)
• Optimal unilocal virtual quantum broadcasting [5.80377843790023]
  We introduce protocols that can be approximated using physical operations with minimal cost. We formalize the simulation cost of a virtual quantum broadcasting protocol into a semidefinite programming problem.
  arXiv  Detail & Related papers  (2023-10-23T17:56:02Z)
• Quantum process tomography of continuous-variable gates using coherent states [49.299443295581064]
  We demonstrate the use of coherent-state quantum process tomography (csQPT) for a bosonic-mode superconducting circuit. We show results for this method by characterizing a logical quantum gate constructed using displacement and SNAP operations on an encoded qubit.
  arXiv  Detail & Related papers  (2023-03-02T18:08:08Z)
• Experimental demonstration of optimal unambiguous two-out-of-four quantum state elimination [52.77024349608834]
  A core principle of quantum theory is that non-orthogonal quantum states cannot be perfectly distinguished with single-shot measurements. Here we implement a quantum state elimination measurement which unambiguously rules out two of four pure, non-orthogonal quantum states.
  arXiv  Detail & Related papers  (2022-06-30T18:00:01Z)
• Faithfulness and sensitivity for ancilla-assisted process tomography [0.0]
  A system-ancilla bipartite state capable of containing the complete information of an unknown quantum channel acting on the system is called faithful. We complete the proof of the equivalence and introduce the generalization of faithfulness to various classes of quantum channels.
  arXiv  Detail & Related papers  (2022-06-13T04:19:22Z)
• Variational Approach to Quantum State Tomography based on Maximal Entropy Formalism [3.6344381605841187]
  We employ the maximal entropy formalism to construct the least biased mixed quantum state that is consistent with the given set of expectation values. We employ a parameterized quantum circuit and a hybrid quantum-classical variational algorithm to obtain such a target state making our recipe easily implementable on a near-term quantum device.
  arXiv  Detail & Related papers  (2022-06-06T01:16:22Z)
• Entanglement and coherence in Bernstein-Vazirani algorithm [58.720142291102135]
  Bernstein-Vazirani algorithm allows one to determine a bit string encoded into an oracle. We analyze in detail the quantum resources in the Bernstein-Vazirani algorithm. We show that in the absence of entanglement, the performance of the algorithm is directly related to the amount of quantum coherence in the initial state.
  arXiv  Detail & Related papers  (2022-05-26T20:32:36Z)
• Quantum Supermaps are Characterized by Locality [0.6445605125467572]
  We provide a new characterisation of quantum supermaps in terms of an axiom that refers only to sequential and parallel composition. We do so by providing a simple definition of locally-applicable transformation on a monoidal category. In our main technical contribution, we use this diagrammatic representation to show that locally-applicable transformations on quantum channels are in one-to-one correspondence with deterministic quantum supermaps.
  arXiv  Detail & Related papers  (2022-05-19T20:36:33Z)
• Improved Quantum Algorithms for Fidelity Estimation [77.34726150561087]
  We develop new and efficient quantum algorithms for fidelity estimation with provable performance guarantees. Our algorithms use advanced quantum linear algebra techniques, such as the quantum singular value transformation. We prove that fidelity estimation to any non-trivial constant additive accuracy is hard in general.
  arXiv  Detail & Related papers  (2022-03-30T02:02:16Z)
• Unconventional mechanism of virtual-state population through dissipation [125.99533416395765]
  We report a phenomenon occurring in open quantum systems by which virtual states can acquire a sizable population in the long time limit. This means that the situation where the virtual state remains unpopulated can be metastable. We show how these results can be relevant for practical questions such as the generation of stable and metastable entangled states in dissipative systems of interacting qubits.
  arXiv  Detail & Related papers  (2022-02-24T17:09:43Z)
• Interactive Protocols for Classically-Verifiable Quantum Advantage [46.093185827838035]
  "Interactions" between a prover and a verifier can bridge the gap between verifiability and implementation. We demonstrate the first implementation of an interactive quantum advantage protocol, using an ion trap quantum computer.
  arXiv  Detail & Related papers  (2021-12-09T19:00:00Z)

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.