activity
20222026
most citedHow to simulate quantum measurement without computing marginals

27 citations · 33 across the 18 of their papers we have counts for

collaborators

18 papers

math.CO2026

The -Conjecture for CIS -Graphs

Yinchen Liu, Quanyu Tang

We prove the -conjecture, which dates back to Gurvich's 1978 thesis. Specifically, let the edges of a complete graph be colored with colors , and for each let $G…

quant-ph2026

Conditional dependence and Scrooge ensembles in shallow random quantum circuits

Yinchen Liu, Max McGinley, Thomas Schuster +1

The output state of a 2D geometrically local shallow random quantum circuit does not have long range correlations due to its lightcone structure. But this changes if one measures a…

math.CO2026

A positive square-energy strengthening of Turán's theorem

Yinchen Liu, Quanyu Tang, Shengtong Zhang

Let be an -vertex graph with clique number , and let denote the sum of the squared positive adjacency eigenvalues. We prove that $$ \sqrt{s^+(G)}\le\left(1-\f…

math.CO2026

The positive and negative square-energy conjecture

Yinchen Liu, Quanyu Tang, Shengtong Zhang

Let and denote the sums of the squares of the positive and negative adjacency eigenvalues of a graph , respectively. We prove the conjecture of Elphick, Farber…

quant-ph2026

Efficient quantum algorithm for Heisenberg spin systems

Sergey Bravyi, David Gosset, Yinchen Liu +1

We consider a broad family of Heisenberg-type quantum spin systems that were studied by Suzuki and Fisher in 1971. This family includes, for example, the Heisenberg antiferromagnet…

math.CO2026

Path-Minimality of -Energy for Connected Graphs

Yinchen Liu, Quanyu Tang

Let be a simple connected graph on vertices, and let be the eigenvalues of its adjacency matrix . For , define the -energy of $G…

math.CO2026

Path-Minimality for Positive -Energies, Laplacian-Type Spectra, and Line Graphs

Yinchen Liu, Quanyu Tang

We derive several applications of the path-minimality theorem for adjacency -energy proved in the companion paper. First, we prove the sharp inequality $$ \mathcal E_p^+(G)\ge \…

cs.CC2026

On the Complexity of the Circuit Width Problem

Zhengfeng Ji, Yinchen Liu, Zhe'ou Zhou

Montanaro's polynomial representation expresses amplitudes of quantum circuits over the gates , , , and as normalized gaps of degree-three polynomials over $\mathbb…

quant-ph2026

Sample-efficient benchmarking of shallow all-to-all random quantum circuits

Gregory Bentsen, Bill Fefferman, Soumik Ghosh +2

Random circuit sampling (RCS) remains one of the most competitive frameworks for demonstrating quantum advantage in near-term noisy intermediate-scale quantum (NISQ) hardware. Unfo…

cs.DS2026

Turnstile Streaming Algorithms Might (Still) as Well Be Linear Sketches, for Polynomial-Length Streams

Cheng Jiang, Yinchen Liu, Huacheng Yu

A fundamental question in streaming complexity is whether every space-efficient turnstile algorithm is implicitly a linear sketch. The landmark work of Li, Nguyen, and Woodruff [LN…

quant-ph2026

Lee-Yang tensors and Hamiltonian complexity

Benjamin Wong, Sergey Bravyi, David Gosset +1

A complex tensor with binary indices can be identified with a multilinear polynomial in complex variables. We say it is a Lee-Yang tensor with radius if the polynomial…

quant-ph2024

On the complexity of sampling from shallow Brownian circuits

Gregory Bentsen, Bill Fefferman, Soumik Ghosh +2

While many statistical properties of deep random quantum circuits can be deduced, often rigorously and other times heuristically, by an approximation to global Haar-random unitarie…

math.CO2024

On a conjecture of Nikiforov concerning the minimal -energy of connected graphs

Quanyu Tang, Yinchen Liu, Wei Wang

For a given simple graph \( G \), the \( p \)-energy of \( G \), denoted by \( \mathcal{E}_p(G) \), is defined as the sum of the \( p \)-th power of the absolute values of the eige…

math.CO2024

On the Positive and Negative -Energies of Graphs under Edge Addition

Quanyu Tang, Yinchen Liu, Wei Wang

In this paper, we introduce the concepts of positive and negative -energies of graphs and investigate their behavior under edge addition. Specifically, we generalize the classic…

quant-ph2024★ 1 cited

Quantum advantage from measurement-induced entanglement in random shallow circuits

Adam Bene Watts, David Gosset, Yinchen Liu +1

We study random constant-depth quantum circuits in a two-dimensional architecture. While these circuits only produce entanglement between nearby qubits on the lattice, long-range e…

quant-ph2023

Classical simulation of peaked shallow quantum circuits

Sergey Bravyi, David Gosset, Yinchen Liu

An -qubit quantum circuit is said to be peaked if it has an output probability that is at least inverse-polynomially large as a function of . We describe a classical algorith…

quant-ph2022★ 5 cited

A rapidly mixing Markov chain from any gapped quantum many-body system

Sergey Bravyi, Giuseppe Carleo, David Gosset +1

We consider the computational task of sampling a bit string from a distribution , where is the unique ground state of a local Hamiltonian .…

quant-ph2022★ 27 cited

How to simulate quantum measurement without computing marginals

Sergey Bravyi, David Gosset, Yinchen Liu

We describe and analyze algorithms for classically simulating measurement of an -qubit quantum state in the standard basis, that is, sampling a bit string from the proba…