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A fundamental objective in quantum information science is to determine the cost in classical resources of simulating a particular quantum system. The classical simulation cost is quantified by the signaling dimension which specifies the…

Quantum Physics · Physics 2022-03-29 Brian Doolittle , Eric Chitambar

In this paper we establish important relations between Hamiltonian dynamics and Riemannian structures on phase spaces for unitarily evolving finite level quantum systems in mixed states. We show that the energy dispersion (i.e. $1/\hbar$…

Quantum Physics · Physics 2013-02-08 Ole Andersson , Hoshang Heydari

Simulating quantum systems with their environments often requires non-unitary operations, and mapping these to quantum devices often involves expensive dilations or prohibitive measurement costs to achieve desired precisions. Building on…

Quantum Physics · Physics 2025-02-03 Aman Mehta , Scott E. Smart , Joseph Peetz , David A. Mazziotti , Prineha Narang

In this article, we investigate various physical implications of quantum circuit complexity using squeezed state formalism of Primordial Gravitational Waves (PGW). Recently quantum information theoretic concepts, such as entanglement…

General Relativity and Quantum Cosmology · Physics 2023-03-07 Kiran Adhikari , Sayantan Choudhury , Hardey N. Pandya , Rohan Srivastava

We show that a sequence $\{\Phi_n\}$ of quantum channels strongly converges to a quantum channel $\Phi_0$ if and only if there exist a common environment for all the channels and a corresponding sequence $\{V_n\}$ of Stinespring isometries…

Quantum Physics · Physics 2020-09-01 M. E. Shirokov

We show that every finite-dimensional quantum system with Markovian (i.e., GKLS-generated) time evolution has an autonomous unitary dilation which can be dynamically decoupled. Since there is also always an autonomous unitary dilation which…

Mathematical Physics · Physics 2023-01-18 Daniel Burgarth , Paolo Facchi , Robin Hillier

As a new step towards defining complexity for quantum field theories, we map Nielsen operator complexity for $SU(N)$ gates to two-dimensional hydrodynamics. We develop a tractable large $N$ limit that leads to regular geometries on the…

High Energy Physics - Theory · Physics 2022-10-05 Pablo Basteiro , Johanna Erdmenger , Pascal Fries , Florian Goth , Ioannis Matthaiakakis , René Meyer

It is widely accepted that noisy quantum devices are limited to logarithmic depth circuits unless mid-circuit measurements and error correction are employed. However, this conclusion holds only for unital error channels, such as…

Quantum Physics · Physics 2024-11-08 Oles Shtanko , Kunal Sharma

We compare two sets of multimode quantum channels acting on a finite collection of harmonic oscillators: (a) the set of linear bosonic channels, whose action is described as a linear transformation at the phase space level; and (b) Gaussian…

Quantum Physics · Physics 2018-11-14 Ludovico Lami , Krishna Kumar Sabapathy , Andreas Winter

Exact solutions in interacting many-body systems are scarce but extremely valuable since they provide insights into the dynamics. Dual-unitary models are examples in one spatial dimension where this is possible. These brick-wall quantum…

Statistical Mechanics · Physics 2023-05-24 Pavel Kos , Georgios Styliaris

In a wide range of quantum gravity theories, quasiclassical geometries, which are solutions to the Einstein field equations approximately, are described by "coherent states." Here we propose a Hamiltonian formalism for gravitational…

General Relativity and Quantum Cosmology · Physics 2025-12-01 Sijia Wang , Achintya Sajeendran , Dong-han Yeom , Robert B. Mann , Joshua Foo

We construct a classical algorithm that designs quantum circuits for algorithmic quantum simulation of arbitrary qudit channels on fault-tolerant quantum computers within a pre-specified error tolerance with respect to diamond-norm…

Quantum Physics · Physics 2015-09-23 Dong-Sheng Wang , Barry C. Sanders

In optimal quantum-mechanical evolutions, motion can take place along paths of minimal length within an optimal time frame. Alternatively, optimal evolutions may occur along established paths without any waste of energy resources and…

Quantum Physics · Physics 2026-01-16 Carlo Cafaro , James Schneeloch

This work develops a symplectic framework for quantum computing to be applied to classical Hamiltonian systems, exploiting the intrinsic geometric compatibility between unitary quantum evolution and symplectic phase-space dynamics in a…

Inevitably, assessing the overall performance of a quantum computer must rely on characterizing some of its elementary constituents and, from this information, formulate a broader statement concerning more complex constructions thereof.…

Quantum Physics · Physics 2019-08-14 Arnaud Carignan-Dugas , Matthew Alexander , Joseph Emerson

It has been known for almost 30 years that quantum circuits with interspersed depolarizing noise converge to the uniform distribution at $\omega(\log n)$ depth, where $n$ is the number of qubits, making them classically simulable. We show…

Quantum Physics · Physics 2025-10-09 Jon Nelson , Joel Rajakumar , Michael J. Gullans

Combining machine learning and quantum computation is a potential path towards powerful applications on quantum devices. Regarding this, quantum neural networks are a prominent approach. In this work, we present a novel architecture for…

Quantum Physics · Physics 2025-02-14 Tobias C. Sutter , Christopher Popp , Beatrix C. Hiesmayr

The main goal of this thesis is to quantize the Einstein-Hilbert action extended by the quadratic curvature terms within the canonical quantization approach, thus formulating quantum geometrodynamics of the higher derivative theories. The…

General Relativity and Quantum Cosmology · Physics 2020-08-18 Branislav Nikolic

We show that quantum circuit complexity for the unitary time evolution operator of any time-independent Hamiltonian is bounded by linear growth at early times, independent of any choices of the fundamental gates or cost metric. Deviations…

High Energy Physics - Theory · Physics 2024-10-15 S. Shajidul Haque , Ghadir Jafari , Bret Underwood

For any quantum algorithm given by a path in the space of unitary operators we define the computational complexity as the typical computational time associated with the path. This time is defined using a quantum time estimator associated…

High Energy Physics - Theory · Physics 2020-04-01 Cesar Gomez