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Related papers: Fast Amplification of QMA

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We study a variant of QMA where quantum proofs have no relative phase (i.e. non-negative amplitudes, up to a global phase). If only completeness is modified, this class is equal to QMA [arXiv:1410.2882]; but if both completeness and…

Quantum Physics · Physics 2023-06-26 Roozbeh Bassirian , Bill Fefferman , Kunal Marwaha

We prove that two-way probabilistic and quantum finite automata (2PFA's and 2QFA's) can be considerably more concise than both their one-way versions (1PFA's and 1QFA's), and two-way nondeterministic finite automata (2NFA's). For this…

Computational Complexity · Computer Science 2014-01-29 Abuzer Yakaryilmaz , A. C. Cem Say

The entanglement witness is an important and experimentally applicable tool for entanglement detection. In this paper, we provide a nonlinear improvement of any entanglement witness for $2\otimes d$ quantum systems. Compared with any…

Quantum Physics · Physics 2020-01-16 Shu-Qian Shen , Jin-Min Liang , Ming Li , Juan Yu , Shao-Ming Fei

Amplitude amplification provides a quadratic speed-up for an array of quantum algorithms when run on a quantum machine perfectly isolated from its environment. However, the advantage is substantially diminished as the NISQ-era quantum…

Quantum Physics · Physics 2022-11-29 Debashis Ganguly , Wonsun Ahn

Retrieval augmented Question Answering (QA) helps QA models overcome knowledge gaps by incorporating retrieved evidence, typically a set of passages, alongside the question at test time. Previous studies show that this approach improves QA…

Computation and Language · Computer Science 2025-09-12 Laura Perez-Beltrachini , Mirella Lapata

We present two new quantum algorithms. Our first algorithm is a generalization of amplitude amplification to the case when parts of the quantum algorithm that is being amplified stop at different times. Our second algorithm uses the first…

Quantum Physics · Physics 2010-11-16 Andris Ambainis

We find a modification to QMA where having one quantum proof is strictly less powerful than having two unentangled proofs, assuming EXP $\ne$ NEXP. This gives a new route to prove QMA(2) = NEXP that overcomes the primary drawback of a…

Quantum Physics · Physics 2024-10-28 Roozbeh Bassirian , Bill Fefferman , Itai Leigh , Kunal Marwaha , Pei Wu

Recently we find several candidates of quantum algorithms that may be implementable in near-term devices for estimating the amplitude of a given quantum state, which is a core sub- routine in various computing tasks such as the Monte Carlo…

Quantum Physics · Physics 2021-10-12 Tomoki Tanaka , Yohichi Suzuki , Shumpei Uno , Rudy Raymond , Tamiya Onodera , Naoki Yamamoto

We introduce two methods for quantum process and detector tomography. In the quantum process tomography method, we develop an analytical procedure for projecting the linear inversion estimation of a quantum channel onto the set of…

Quantum Physics · Physics 2025-01-10 Júlia Barberà-Rodríguez , Leonardo Zambrano , Antonio Acín , Donato Farina

The success probability in an ancilla based circuit generally decreases exponentially in the number of qubits consisted in the ancilla. Although the probability can be amplified through the amplitude amplification process, the input…

Quantum Physics · Physics 2016-12-13 Ammar Daskin , Sabre Kais

We improve on the results of [A. Jackson et al. Proc. Natl. Acad. Sci. U.S.A 121 (6). 2024] on the verification of analogue quantum simulators by eliminating the use of universal Hamiltonians, removing the need for two-qubit gates, and no…

Quantum Physics · Physics 2025-02-11 Andrew Jackson , Animesh Datta

Amplification of quantum states is inevitably accompanied with the introduction of noise at the output. For protocols that are probabilistic with heralded success, noiseless linear amplification in theory may still possible. When the…

Quantum Physics · Physics 2017-04-28 Syed Assad , Mark Bradshaw , Ping Koy Lam

Quantum algorithms for diverse problems, including search and optimization problems, require the implementation of a reflection operator over a target state. Commonly, such reflections are approximately implemented using phase estimation.…

Quantum Physics · Physics 2018-03-08 Anirban Narayan Chowdhury , Yigit Subasi , Rolando D. Somma

Quantum Amplitude Amplification (QAA), the generalization of Grover's algorithm, is capable of yielding optimal solutions to combinatorial optimization problems with high probabilities. In this work we extend the conventional 2-dimensional…

Quantum Physics · Physics 2026-01-16 Daniel Koch , Brian Pardo , Kip Nieman

We propose using variational quantum algorithms (VQAs) to simulate established quantum algorithms under realistic noise conditions, aiming to surpass the fidelity of theoretical circuits in noisy environments. Focusing on the Quantum…

Watrous had presented the first proof of zero-knowledge property of a proof system against a quantum verifier. The key of the proof is the construction of a quantum simulator. In the construction, the 'failure state' is rotated to the…

Quantum Physics · Physics 2007-05-23 Keiji Matsumoto

Overcoming the influence of noise and imperfections is a major challenge in quantum computing. Here, we present an approach based on applying a desired unitary computation in superposition between the system of interest and some auxiliary…

We revisit the Pseudo-Bayesian approach to the problem of estimating density matrix in quantum state tomography in this paper. Pseudo-Bayesian inference has been shown to offer a powerful paradign for quantum tomography with attractive…

Applications · Statistics 2023-09-15 The Tien Mai

Amplitude filtering is concerned with identifying basis-states in a superposition whose amplitudes are greater than a specified threshold; probability filtering is defined analogously for probabilities. Given the scarcity of qubits, the…

Quantum Physics · Physics 2023-01-23 Debajyoti Bera , Tharrmashastha Sapv

Quantum amplification is essential for various quantum technologies such as communication and weak-signal detection. However, its practical use is still limited due to inevitable device fragility that brings about distortion in the output…

Quantum Physics · Physics 2016-05-09 Naoki Yamamoto