Field
Quantum Algorithm
55 records: 52 unsolved, 3 solved. Filter the catalog by this field →
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Linear-size exact quantum Fourier transform
Can the exact quantum Fourier transform on \(n\) qubits be implemented with \(O(n)\) one- and two-qubit gates?
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Unrestricted quantum time–space tradeoff for collision finding
Does every unrestricted quantum collision-finding algorithm satisfy \(T^2S=\Omega(N\log N)\)?
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Subquadratic total quantum gate complexity of RSA factoring
Can every balanced RSA semiprime be factored with polynomially subquadratic total quantum gate complexity?
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Sparse Hamiltonian learning without short-time control
Can every polynomially sparse Hamiltonian be learned with Heisenberg-limited total evolution time when every oracle call has a fixed minimum duration?
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Sublinear logical quantum space for RSA factoring
Can every balanced RSA semiprime be factored in polynomial time using sublinear logical quantum space?
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Sampling weakly depolarized constant-depth random circuits
Can weak final-layer depolarizing noise make constant-depth two-dimensional Haar-random circuits classically samplable to inverse-polynomial total-variation error?
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Multiplicative sparse-access lower bound for quantum linear systems
Does sparse-oracle quantum linear-system solving require \(\Omega(\kappa\sqrt{s}\log(1/\varepsilon))\) queries in the worst case?
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Conditional-correlation decay in amplitude-damped random circuits
Do computational-basis outputs of one-dimensional Haar-random circuits with fixed amplitude damping have conditional mutual information that decays exponentially with separation, uniformly in circuit depth?
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Unknown-structure Hamiltonian learning from Gibbs states at all temperatures
Can every bounded-degree local Hamiltonian with unknown interaction support be learned efficiently from copies of its Gibbs state at any fixed inverse temperature?
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Uniform modified log-Sobolev constant for one-dimensional Gibbs samplers
Do normalized one-dimensional Chen–Kastoryano–Gilyén Gibbs samplers have a positive modified log-Sobolev constant uniformly in system size at every fixed finite temperature?
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Pseudorandom unitaries from ordinary random two-qubit circuits
Does a polynomial-length random walk generated by ordinary two-qubit gates form a pseudorandom-unitary ensemble?
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Exact spectral gap of random Pauli rotations
Is the exact Haar-mixing spectral gap of uniformly random Pauli rotations equal to \(2^n(2^n-3)/(8(4^n-1))\) for every \(n\geq4\)?
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Single-copy identity testing of local Gibbs states
What is the minimax copy complexity of identity testing two unknown \(k\)-local Gibbs states using only measurements on individual copies?
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CNOT-count and depth frontier for quantum Golay state preparation
What is the exact CNOT-count and depth frontier for ancilla-free Clifford preparation of the logical zero state of the \([[23,1,7]]_2\) quantum Golay code?
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Endpoint quantum KKL inequality for Boolean observables
Does the Montanaro–Osborne \(L^2\) quantum KKL inequality hold for every Boolean quantum observable?
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Aaronson–Ambainis conjecture
Must every bounded low-degree real polynomial on the Boolean cube with non-negligible variance have a variable of inverse-polynomial influence?
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Average-case approximation hardness of random-circuit output probabilities
Does there exist a fixed family of \(n\)-qubit circuit layouts with \(m=\operatorname{poly}(n)\) one- and two-qubit gates for which the following task is \(\#\mathrm{P}\)-hard?
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Quantum query complexity of Triangle Finding
What is the bounded-error quantum query complexity of finding a triangle in an \(n\)-vertex graph given oracle access to its adjacency matrix?
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Asymptotic growth of the stabilizer rank of T-state tensor powers
Does the exact stabilizer rank of the tensor powers of the single-qubit magic state \(|T\rangle\) grow polynomially in the number of copies, or is it not polynomially bounded?
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Efficient determination of the Clifford-hierarchy level of bounded-degree permutation gates
For each fixed degree bound \(d\geq2\), is there a deterministic polynomial-time algorithm that computes the Clifford-hierarchy level of an \(n\)-qubit permutation gate from degree-at-most-\(d\) algebraic normal forms of the permutation and its inverse, or reports…
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Smallest qubit number for a non-semi-Clifford third-level gate
What is the smallest number of qubits on which the third level of the Clifford hierarchy contains a gate that is not semi-Clifford?
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Linear-size logarithmic-depth encoders for good quantum LDPC codes
Does some family of asymptotically good qubit CSS LDPC codes admit unitary encoding circuits with linearly many gates and logarithmic depth?
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Semi-Clifford structure of two-qudit hierarchy gates above the third level
Is every two-qudit gate in every level \(k\geq4\) of the Clifford hierarchy semi-Clifford when the local dimension is an odd prime?
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Highest Clifford-hierarchy level of controlled gates with higher-level targets
What is the highest Clifford-hierarchy level that a controlled gate can reach when its target lies in a given level \(k\geq3\) and has a given Pauli periodicity, and is that level bounded independently of the number of target qubits?
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Geelen’s simulation conjecture for vertex-minor-closed graph classes
Does Geelen’s simulation conjecture hold for every nonempty proper class \(\mathcal C\subsetneq\mathcal G_{\mathrm{fin}}\) of finite simple graphs that is closed under isomorphism, local complementation, and vertex deletion?
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Deterministic quadratic-size vertex-minor-universal graphs
Does there exist an absolute constant \(C>0\) and a deterministic algorithm that, for each integer \(k\geq2\) supplied in unary, runs in time \(k^{O(1)}\) and outputs a \(k\)-vertex-minor-universal graph with at most \(Ck^2\) vertices?
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Permanent-of-Gaussians Conjecture
Is the following Gaussian permanent estimation task \(\#\mathrm P\)-hard under randomized polynomial-time oracle reductions?
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Multi-slot overhead of virtual channel conjugation
What is the optimal quasiprobability overhead of implementing the complex conjugate of an unknown quantum channel from \(n\) queries?
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Universality of arbitrary self-adjoint polynomial Hamiltonians
Can every physical bosonic unitary be approximated by a single self-adjoint polynomial Hamiltonian evolution at any finite input energy?
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Anticoncentration of independent complex Gaussian hafnians
Do independent complex Gaussian hafnians satisfy a polynomial lower-tail bound at their root-mean-square scale?
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Universality of every fixed non-Gaussian polynomial generator
Does every fixed non-Gaussian polynomial Hamiltonian become universal when all Gaussian controls are available?
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Compact-time validity of the rotating wave approximation
Does the Jaynes–Cummings evolution approximate the Rabi evolution strongly and uniformly on each compact time interval in the high-frequency limit?
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Average-case additive hardness of squared complex Gaussian hafnians
Is additive estimation of squared complex Gaussian hafnians \(\#\mathrm P\)-hard under randomized polynomial-time oracle reductions?
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Permanent anticoncentration for complex Gaussian matrices
Do complex Gaussian permanents satisfy a polynomial lower-tail bound at their root-mean-square scale?
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Fully polynomial sampling of boson sampling with constant photon transmission
For every fixed rational transmission \(0<\eta<1\), is boson sampling with independent photon loss classically samplable in fully polynomial time?
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Polynomial-time quantum algorithm for Graph Isomorphism
Does the Graph Isomorphism problem admit a polynomial-time quantum algorithm?
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Optimal precision dependence of low-energy Hamiltonian simulation
What is the tight precision dependence of worst-case query complexity for low-energy simulation in the regime (2)?
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Simultaneously optimal queries to both quantum linear-system oracles
Can one quantum linear-system algorithm attain both query bounds in (2) simultaneously?
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Polynomial-time local-unitary equivalence of graph states
Does a deterministic classical algorithm running in \(n^{O(1)}\) time decide local-unitary equivalence of arbitrary graph states on \(n\) labelled qubits?
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Quantum query complexity of Welded Tree path-finding
Does finding an explicit ENTRANCE-to-EXIT path in the standard Welded Tree oracle problem require exponentially many quantum queries?
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Polynomial-time quantum algorithm for approximate Shortest Vector Problem
Does the polynomial-factor approximate Shortest Vector Problem admit a polynomial-time quantum algorithm?
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Polynomial-time quantum algorithm for the Dihedral Hidden Subgroup Problem
Does the Dihedral Hidden Subgroup Problem admit a quantum algorithm whose running time is polynomial in the input length?
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QMA(2) versus QMA
Is every promise problem verifiable by a quantum Merlin-Arthur protocol with two unentangled witnesses also verifiable by a protocol with a single arbitrary witness, that is, is \(\mathsf{QMA}(2) = \mathsf{QMA}\) in the standard, unrelativized setting?
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Computability of ordinary quantum capacity
Is the ordinary unassisted quantum capacity a computable function of a finite description of a finite-dimensional quantum channel?
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Polynomial-time quantum algorithm for Learning With Errors
Does the Learning With Errors problem in its standard worst-case-hard parameter regime admit a polynomial-time quantum algorithm?
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Parity is not in QAC0
Can polynomial-size constant-depth \(\mathsf{QAC}^0\) circuits compute the parity function, or equivalently, is \(\mathrm{PARITY}\notin\mathsf{QAC}^0\)?
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Is bipartite Quantum Max-Cut in BPP?
Is the following bipartite Quantum Max-Cut promise problem in \(\mathrm{BPP}\)?
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Average-case approximation hardness of random Ising partition functions
Is it \(\#\mathrm{P}\)-hard to approximate \(|Z_R|^2\) to relative multiplicative error \(a+o(1)\) on a \(b\) fraction of random Ising instances?
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Average-case approximation hardness of squared normalized gaps of random cubic polynomials
Is it \(\#\mathrm{P}\)-hard to approximate \(\operatorname{ngap}(f)^2\) to relative multiplicative error \(a+o(1)\) on a \(b\) fraction of uniformly random degree-3 polynomials over \(\mathbb{F}_2\)?
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Universal purification with classically simulable operations
Can classically simulable operations purify an unknown depolarized pure state from any number of copies?
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Uniformly efficient HSW pretty-good decoding
Can Holevo–Schumacher–Westmoreland codebooks operating at every rate below their ensemble Holevo information be chosen so that their square-root, or pretty-good, measurements have uniform quantum implementations whose cost is polynomial in the blocklength and…
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The quantum PCP conjecture
Is the constant-relative-gap local Hamiltonian problem QMA-hard?
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Unconditional classical verification with one quantum prover
Does every language \(L\in\mathsf{BQP}\) admit a single-prover interactive proof with a fully classical verifier, an efficient quantum honest prover, and information-theoretic soundness?
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Collective cost of tensor-power state preparation
Determine the asymptotic weighted circuit cost of preparing tensor powers of a known pure state, and characterize when collective preparation is cheaper per copy than independent preparation.
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Constant trace-distance separability testing
What is the computational complexity of testing bipartite separability with a constant trace-distance promise gap?
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