428 citations · 559 across the 22 of their papers we have counts for
24 papers
Infinite magic and the emergence of the continuum
Leo Shaposhnik, Lorenzo Leone, Lennart Bittel +3
Which features of a quantum state are needed for a relativistic quantum field theory to emerge from a lattice system? We address this question by establishing a quantitative relati…
Adaptivity is all you need: Optimal stabilizer learning using just single-copy measurements
L. Bittel, J. Eisert, W. Gong +2
Stabilizer states are central to quantum computing, underlying quantum error correction, benchmarking, and efficient classical simulation. Yet their learnability exhibits a strikin…
Efficient learning of Clifford disentanglers and typical -doped unitaries with exponentially more gates
Gerard Aguilar, Sofiene Jerbi, Jens Eisert +1
Highly entangled and highly non-stabilizer quantum states need not be hard to learn. We give efficient algorithms for testing and recovering hidden tensor-product structure in unkn…
Fermionic entropy: an efficiently measurable strong monotone for non-Gaussianity
Lorenzo Leone, Lennart Bittel
Fermionic Gaussian states form a central class of classically tractable quantum states, while fermionic non-Gaussianity provides the resource required to go beyond free-fermion dyn…
Approximate sampling from decoded quantum interferometry via Markov chain Monte Carlo methods
Elies Gil-Fuster, Matan Ninio, Lennart Bittel +4
Optimization problems are among the leading candidates for industrially relevant quantum advantage. Decoded quantum interferometry (DQI) has been proposed to tackle approximate opt…
Optimal learning of quantum channels in diamond distance
Antonio Anna Mele, Lennart Bittel
Quantum process tomography, the task of estimating an unknown quantum channel, is a central problem in quantum information theory. A long-standing open question is how many uses of…
Is it Gaussian? Testing bosonic quantum states
Filippo Girardi, Freek Witteveen, Francesco Anna Mele +4
Gaussian states are widely regarded as one of the most relevant classes of continuous-variable (CV) quantum states, as they naturally arise in physical systems and play a key role…
Adaptively secure unitary designs with constant non-Clifford cost
Lennart Bittel, Lorenzo Leone
Randomness is a fundamental resource in quantum information, with crucial applications in cryptography, algorithms, and error correction. A central challenge is to construct unitar…
Energy-independent tomography of Gaussian states
Lennart Bittel, Francesco Anna Mele, Francesco A. Mele +3
The exploration of tomography of bosonic Gaussian states is presumably as old as quantum optics, but only recently, their precise and rigorous study have been moving into the focus…
Classical simulation of noisy quantum circuits via locally entanglement-optimal unravelings
Simon Cichy, Paul K. Faehrmann, Lennart Bittel +2
Classical simulations of noisy quantum circuits are instrumental to our understanding of the behavior of real-world quantum systems and the identification of regimes where one expe…
Operational interpretation of the Stabilizer Entropy
Lennart Bittel, Lorenzo Leone
Magic-state resource theory is a fundamental framework with far-reaching applications in quantum error correction and the classical simulation of quantum systems. Recent advances h…
Non-Clifford Cost of Random Unitaries
Lorenzo Leone, Salvatore F. E. Oliviero, Alioscia Hamma +2
Recent years have enjoyed a strong interest in exploring properties and applications of random quantum circuits. In this work, we explore the ensemble of -doped Clifford circuit…
A complete theory of the Clifford commutant
Lennart Bittel, Jens Eisert, Lorenzo Leone +2
The Clifford group plays a central role in quantum information science. It is the building block for many error-correcting schemes and matches the first three moments of the Haar m…
Optimal estimates of trace distance between bosonic Gaussian states and applications to learning
Lennart Bittel, Francesco Anna Mele, Antonio Anna Mele +2
Gaussian states of bosonic quantum systems enjoy numerous technological applications and are ubiquitous in nature. Their significance lies in their simplicity, which in turn rests…
Optimal trace-distance bounds for free-fermionic states: Testing and improved tomography
Lennart Bittel, Antonio Anna Mele, Jens Eisert +1
Free-fermionic states, also known as fermionic Gaussian states, represent an important class of quantum states ubiquitous in physics. They are uniquely and efficiently described by…
Experimental measurement and a physical interpretation of quantum shadow enumerators
Daniel Miller, Kyano Levi, Lukas Postler +18
Throughout its history, the theory of quantum error correction has heavily benefited from translating classical concepts into the quantum setting. In particular, classical notions…
Full classification of Pauli Lie algebras
Gerard Aguilar, Simon Cichy, Jens Eisert +1
Lie groups, and therefore Lie algebras, are fundamental structures in quantum physics that determine the space of possible trajectories of evolving systems. However, classification…
Learning quantum states of continuous variable systems
Francesco Anna Mele, Antonio Anna Mele, Lennart Bittel +5
Quantum state tomography, aimed at deriving a classical description of an unknown state from measurement data, is a fundamental task in quantum physics. In this work, we analyse th…
Stabilizer entropies are monotones for magic-state resource theory
Lorenzo Leone, Lennart Bittel
Magic-state resource theory is a powerful tool with applications in quantum error correction, many-body physics, and classical simulation of quantum dynamics. Despite its broad sco…
PAC-learning of free-fermionic states is NP-hard
Lennart Bittel, Antonio A. Mele, Jens Eisert +1
Free-fermionic states, also known as matchgates or Gaussian states, are a fundamental class of quantum states due to their efficient classical simulability and their crucial role a…
Optimizing the depth of variational quantum algorithms is strongly QCMA-hard to approximate
Lennart Bittel, Sevag Gharibian, Martin Kliesch
Variational Quantum Algorithms (VQAs), such as the Quantum Approximate Optimization Algorithm (QAOA) of [Farhi, Goldstone, Gutmann, 2014], have seen intense study towards near-term…
Fast gradient estimation for variational quantum algorithms
Lennart Bittel, Jens Watty, Martin Kliesch
Many optimization methods for training variational quantum algorithms are based on estimating gradients of the cost function. Due to the statistical nature of quantum measurements,…
Scalable approach to many-body localization via quantum data
Alexander Gresch, Lennart Bittel, Martin Kliesch
We are interested in how quantum data can allow for practical solutions to otherwise difficult computational problems. A notoriously difficult phenomenon from quantum many-body phy…
Training variational quantum algorithms is NP-hard
Lennart Bittel, Martin Kliesch
Variational quantum algorithms are proposed to solve relevant computational problems on near term quantum devices. Popular versions are variational quantum eigensolvers and quantum…