Discriminating mixed qubit states with collective measurements

• URL: http://arxiv.org/abs/2302.08882v2
• Date: Thu, 23 Nov 2023 04:46:04 GMT
• Title: Discriminating mixed qubit states with collective measurements
• Authors: Lorcan O. Conlon, Falk Eilenberger, Ping Koy Lam and Syed M. Assad
• Abstract summary: We propose and experimentally demonstrate a protocol for distinguishing two copies of single qubit states using collective measurements. We implement our measurements on an IBM Q System One device, a superconducting quantum processor.
• Score: 0.2621730497733947
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: It is a central fact in quantum mechanics that non-orthogonal states cannot be distinguished perfectly. This property ensures the security of quantum key distribution. It is therefore an important task in quantum communication to design and implement strategies to optimally distinguish quantum states. In general, when we have access to multiple copies of quantum states the optimal measurement will be a collective measurement. However, to date, collective measurements have not been used to enhance quantum state discrimination. One of the main reasons for this is the fact that, in the usual state discrimination setting with equal prior probabilities, at least three copies of a quantum state are required to be measured collectively to outperform separable measurements. This is very challenging experimentally. In this work, by considering unequal prior probabilities, we propose and experimentally demonstrate a protocol for distinguishing two copies of single qubit states using collective measurements which achieves a lower probability of error than can be achieved by any non-entangling measurement. We implement our measurements on an IBM Q System One device, a superconducting quantum processor. Additionally, we implemented collective measurements on three and four copies of the unknown state and found they performed poorly.

Related papers

• Optimal discrimination of quantum sequences [13.39567116041819]
  Key concept of quantum information theory is that accessing information encoded in a quantum system requires us to discriminate between several possible states the system could be in. In this paper, we prove that if the members of a given sequence are drawn secretly and independently from an ensemble or even from different ensembles, the optimum success probability is achievable by fixed local measurements on the individual members of the sequence.
  arXiv  Detail & Related papers  (2024-09-13T10:48:16Z)
• A computational test of quantum contextuality, and even simpler proofs of quantumness [43.25018099464869]
  We show that an arbitrary contextuality game can be compiled into an operational "test of contextuality" involving a single quantum device. Our work can be seen as using cryptography to enforce spatial separation within subsystems of a single quantum device.
  arXiv  Detail & Related papers  (2024-05-10T19:30:23Z)
• Measurement-Device-Independent Detection of Beyond-Quantum State [53.64687146666141]
  We propose a measurement-device-independent (MDI) test for beyond-quantum state detection. We discuss the importance of tomographic completeness of the input sets to the detection.
  arXiv  Detail & Related papers  (2023-12-11T06:40:13Z)
• All pure bipartite entangled states can be semi-self-tested with only one measurement setting on each party [1.6629141734354616]
  We prove that an arbitrary $dtimes d$ bipartite pure state can be certified completely (up to local unitary transformations) by a certain correlation generated by a single measurement setting on each party. Notably, our protocols do not involve any quantum nonlocality.
  arXiv  Detail & Related papers  (2023-06-13T13:12:07Z)
• Quantum Discord Witness with Uncharacterized Devices [18.751513188036334]
  We propose a new approach using uncharacterized measurements to witness quantum discord of an unknown bipartite state within arbitrary dimension system. The feature of high robustness against device imperfections, such as loss-tolerance and error-tolerance, shows our method is experimentally feasible.
  arXiv  Detail & Related papers  (2023-03-20T14:51:53Z)
• Simple Tests of Quantumness Also Certify Qubits [69.96668065491183]
  A test of quantumness is a protocol that allows a classical verifier to certify (only) that a prover is not classical. We show that tests of quantumness that follow a certain template, which captures recent proposals such as (Kalai et al., 2022) can in fact do much more. Namely, the same protocols can be used for certifying a qubit, a building-block that stands at the heart of applications such as certifiable randomness and classical delegation of quantum computation.
  arXiv  Detail & Related papers  (2023-03-02T14:18:17Z)
• Anticipative measurements in hybrid quantum-classical computation [68.8204255655161]
  We present an approach where the quantum computation is supplemented by a classical result. Taking advantage of its anticipation also leads to a new type of quantum measurements, which we call anticipative. In an anticipative quantum measurement the combination of the results from classical and quantum computations happens only in the end.
  arXiv  Detail & Related papers  (2022-09-12T15:47:44Z)
• Pure state tomography with parallel unentangled measurements [0.9746724603067647]
  We focus on the QST of a pure quantum state using parallel unentangled measurements. We propose two sets of quantum measurements that one can make on a pure state as well as the algorithms that use the measurements outcomes in order to identify the state.
  arXiv  Detail & Related papers  (2022-08-08T09:49:55Z)
• 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)
• 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)
• Robust self-testing of steerable quantum assemblages and its applications on device-independent quantum certification [0.0]
  Given a Bell inequality, if its maximal quantum violation can be achieved only by a single set of measurements for each party or a single quantum state, up to local unitaries, one refers to such a phenomenon as self-testing. We propose a framework called "robust self-testing of steerable quantum assemblages" Our result is device-independent (DI), i.e., no assumption is made on the shared state and the measurement devices involved.
  arXiv  Detail & Related papers  (2020-02-07T14:50:16Z)

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.