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Related papers: Quantum state preparation via piecewise QSVT

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Studies on quantum algorithms for ground state energy estimation often assume perfect ground state preparation; however, in reality the initial state will have imperfect overlap with the true ground state. Here we address that problem in…

We propose a scheme for an exact efficient transformation of a tensor product state of many identically prepared qubits into a state of a logarithmically small number of qubits. Using a quadratic number of elementary quantum gates we…

Quantum Physics · Physics 2010-03-31 Martin Plesch , Vladimir Buzek

Quantum state preparation is an important subroutine for quantum computing. We show that any $n$-qubit quantum state can be prepared with a $\Theta(n)$-depth circuit using only single- and two-qubit gates, although with a cost of an…

Quantum Physics · Physics 2023-04-25 Xiao-Ming Zhang , Tongyang Li , Xiao Yuan

State preparation is a fundamental routine in quantum computation, for which many algorithms have been proposed. Among them, perhaps the simplest one is the Grover-Rudolph algorithm. In this paper, we analyse the performance of this…

Quantum Physics · Physics 2023-10-31 Debora Ramacciotti , Andreea-Iulia Lefterovici , Antonio F. Rotundo

Quantum Computing allows, in principle, the encoding of the exponentially scaling many-electron wave function onto a linearly scaling qubit register, offering a promising solution to overcome the limitations of traditional quantum chemistry…

Quantum Physics · Physics 2025-10-21 C. Feniou , O. Adjoua , B. Claudon , J. Zylberman , E. Giner , J. -P. Piquemal

Quantum state preparation is a fundamental primitive in quantum algorithms for encoding classical data into quantum amplitudes. We compare the cost of preparing general $n$-qubit states with real amplitudes using two common paradigms:…

Quantum Physics · Physics 2026-05-20 Diyi Liu , Hanyu Wang , Shuchen Zhu , Jason Cong , Wibe A. de Jong , Di Fang , Zhen Huang , Costin Iancu , Chao Yang

While the preparation of a general quantum state is challenging, realistic problem instances, such as those encountered in quantum chemistry and quantum machine learning-typically exhibit hierarchical amplitude structures, consisting of a…

Quantum Physics · Physics 2026-01-15 Yue Wang , Xiao-Ming Zhang , Xiao Yuan , Qi Zhao

We present an efficient quantum algorithm for preparing a pure state on a quantum computer, where the quantum state corresponds to that of a molecular system with a given number $m$ of electrons occupying a given number $n$ of spin…

Quantum Physics · Physics 2009-05-01 Hefeng Wang , S. Ashhab , Franco Nori

The quantum simulation of real molecules and materials is one of the most highly anticipated applications of quantum computing. Algorithms for simulating electronic structure using a first-quantized plane wave representation are especially…

Quantum Physics · Physics 2025-01-22 William J. Huggins , Oskar Leimkuhler , Torin F. Stetina , K. Birgitta Whaley

State preparation for quantum algorithms is crucial for achieving high accuracy in quantum chemistry and competing with classical algorithms. The localized active space unitary coupled cluster (LAS-UCC) algorithm iteratively loads a…

Quantum Physics · Physics 2023-06-08 Ruhee D'Cunha , Matthew Otten , Matthew R. Hermes , Laura Gagliardi , Stephen K. Gray

One of the key considerations in the development of Quantum Machine Learning (QML) protocols is the encoding of classical data onto a quantum device. In this chapter we introduce the Matrix Product State representation of quantum systems…

Quantum Physics · Physics 2026-01-15 Chris Nakhl , Maxwell West , Muhammad Usman

Continuous-time quantum walks (CTQWs) on dynamic graphs, referred to as dynamic CTQWs, are a recently introduced universal model of computation that offers a new paradigm in which to envision quantum algorithms. In this work we develop an…

Quantum Physics · Physics 2025-09-29 Alvin Gonzales , Rebekah Herrman , Colin Campbell , Igor Gaidai , Ji Liu , Teague Tomesh , Zain H. Saleem

We demonstrate a technique for optimizing quantum circuits that is analogous to classical windowing. Specifically, we show that small table lookups can allow control qubits to be iterated in groups instead of individually. We present…

Quantum Physics · Physics 2019-05-21 Craig Gidney

Highly entangled quantum states are an ingredient in numerous applications in quantum computing. However, preparing these highly entangled quantum states on currently available quantum computers at high fidelity is limited by ubiquitous…

Quantum Physics · Physics 2025-02-27 Sebastian Brandhofer , Ilia Polian , Stefanie Barz , Daniel Bhatti

The preparation of $n$-qubit quantum states is a cross-cutting subroutine for many quantum algorithms, and the effort to reduce its circuit complexity is a significant challenge. In the literature, the quantum state preparation algorithm by…

Quantum Physics · Physics 2026-02-09 Giacomo Belli , Michele Amoretti

State preparation is a necessary component of many quantum algorithms. In this work, we combine a method for efficiently representing smooth differentiable probability distributions using matrix product states with recently discovered…

Quantum Physics · Physics 2024-02-19 Jason Iaconis , Sonika Johri , Elton Yechao Zhu

We give a pair of algorithms that efficiently learn a quantum state prepared by Clifford gates and $O(\log n)$ non-Clifford gates. Specifically, for an $n$-qubit state $|\psi\rangle$ prepared with at most $t$ non-Clifford gates, our…

Quantum Physics · Physics 2025-11-07 Sabee Grewal , Vishnu Iyer , William Kretschmer , Daniel Liang

Many-body ground state preparation is an important subroutine used in the simulation of physical systems. In this paper, we introduce a flexible and efficient framework for obtaining a state preparation circuit for a large class of…

Quantum Physics · Physics 2024-11-05 Hyun-Soo Kim , Isaac H. Kim , Daniel Ranard

We propose a general scheme for dissipatively preparing arbitrary pure quantum states on a multipartite qubit register in a finite number of basic control blocks. Our "splitting-subspace" approach relies on control resources that are…

Quantum Physics · Physics 2013-11-19 Giacomo Baggio , Francesco Ticozzi , Lorenza Viola

We present a polynomial-time quantum algorithm making a single query (in superposition) to a classical oracle, such that for every state $|\psi\rangle$ there exists a choice of oracle that makes the algorithm construct an exponentially…

Quantum Physics · Physics 2023-09-19 Gregory Rosenthal