The Theory of Quantum Computation, Communication and Cryptography (TQC) is a leading annual international conference for students and researchers working in the theoretical aspects of quantum information science. The scientific objective is to bring together the theoretical quantum information science community to present and discuss the latest advances in the field.
The 19th TQC was hosted by OIST in Okinawa, Japan, in September 2024. It was a hybrid event, with focus on in-person participation. Talks were streamed live.
Potential and Limitations of Near-Term Quantum Computing
Quantum computers promise the efficient solution of some highly structured computational problems that are classically intractable. While for many years they have been primarily objects of theoretical study, only recently have efforts to build intermediate-scale quantum computers taken off. This creates an interesting state of affairs, but at the same time, it begs the question of what such devices are, practically speaking, good for. In this talk, we will present some encouraging as well as—emphasizing the latter—discouraging insights into near-term quantum computing. We will discuss rigorous quantum advantages in paradigmatic problems [1,2] and explore the use of quantum computers in machine learning [3,4] and optimization [5]. The second part of the talk will focus on the significant limitations that arise. We will emphasize identifying limitations to quantum error mitigation for shallow quantum circuits in the worst case [6]. Interestingly, it may depend on the nuances of non-unital quantum noise to what extent quantum computing without error correction may be feasible [7]. We will also provide efficient classical algorithms for instances of quantum algorithms, hence "de-quantizing" them [7-9]. The talk will conclude with the note that quantum simulation remains, to date, one of the most promising applications of near-term quantum devices [10,11].
Forward and Backward Mappings for Quantum Graphical Models
Graphical models offer a unifying framework for various statistical learning algorithms and models. Central to these models are the forward and backward mapping problems, which have been studied through both exact and approximate algorithms. This talk explores these mapping problems within the context of quantum graphical models, where quantum states generalize classical probability distributions. The forward mapping problem involves deriving mean parameters from model parameters and is closely linked to approximating the partition function---a typically challenging task often requiring heuristics and approximations. We'll discuss quantum belief propagation, which has shown success in one-dimensional systems, as well as variational methods such as Markov entropy decomposition that tackle the problem from an optimization perspective. The task of the backward mapping problem aims to compute model parameters from mean parameters. It is related to the Hamiltonian learning problem, a topic of growing interest in quantum information science lately. We'll review some existing algorithms and introduce the quantum iterative scaling (QIS) algorithm that reduces the backward mapping problem to a series of forward mapping problems. We'll present a convergence proof for QIS and demonstrate its advantages over gradient descent methods. Furthermore, we'll explore how quasi-Newton methods can enhance QIS and gradient descent algorithms, showcasing significant efficiency improvements.
DakshitaKhurana
University of Illinois Urbana-Champaign
Understanding Cryptographic Hardness in a Quantum World
A flurry of exciting, recent work has shown that the mathematical hardness required to realize cryptosystems such as bit commitments and secure computation in a quantum world can be significantly weaker than the hardness required for classical cryptography. This talk will discuss recent progress and some remaining challenges in understanding the assumptions that enable cryptography in a quantum world.
Tomoyuki Morimae
Yukawa Institute for Theoretical Physics, Kyoto University
Quantum cryptography without one-way functions
The existence of one-way functions is the minimum assumption in classical cryptography. On the other hand, in quantum cryptography where quantum computing and quantum communications are possible, recent studies have demonstrated that the existence of one-way functions is not necessarily the minimum assumption. Several new fundamental primitives have been introduced, such as pseudorandom unitaries, pseudorandom states, one-way state generators, EFI pairs, and one-way puzzles. They seem to be weaker than one-way functions, but still imply many useful applications, such as secret-key encryption, message authentication codes, digital signatures, private-key quantum money, commitments, and multiparty computations, etc. In this talk, I explain the basics of this “quantum cryptography without one-way functions” and give many open problems that I want to know the answers to.
Sponsors and organization of TQC 2023
Platinum sponsors
JPMorganChase
The Quantum Computing team at JPMorganChase's Global Technology Applied Research Center is at the forefront of advancing both the theoretical and practical aspects of quantum and quantum-inspired algorithms. They are currently seeking talented individuals for summer internships, as well as full-time positions for research scientists and software engineers at all experience levels. Join the firm in pushing the boundaries of quantum computing technology. Apply for open positions here.
Gold sponsors
Google Quantum AI
Gold Sponsor
Google Quantum AI is advancing the state of the art of quantum computing and developing the tools for researchers to operate beyond classical capabilities. Our mission is to make best-in-class quantum computing tools available to the world, enabling humankind to solve problems that would otherwise be impossible.
Horizon Quantum Computing is developing a new generation of programming tools to simplify and expedite the process of developing software for quantum computers. By removing the need for prior quantum computing experience to develop applications for quantum hardware, Horizon’s tools are making the power of quantum computing accessible to every software developer.
Quantinuum's mission is to accelerate quantum computing and use its power to positively transform the world. By applying the laws of quantum physics to computing, we will achieve unprecedented breakthroughs in drug discovery, healthcare, materials science, cybersecurity, energy transformation, and climate change.
Japan National Tourism Organization
Silver Sponsor
JNTO is involved in a broad range of activities both domestically and worldwide, to encourage international tourists from all over the world to visit Japan.
People and Committees of TQC 2024
Steering Committee of TQC 2024
Andris Ambainis, University of Latvia
Eric Chitambar, University of Illinois at Urbana-Champaign
@Poster{P24_382,
title = {A Complete Graphical Language for Linear Optical Circuits with Finite-Photon-Number Sources and Detectors},
author = {Nicolas Heurtel},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_398,
title = {A Cryptographic Perspective on the Verifiability of Quantum Advantage},
author = {Nai-Hui Chia and Honghao Fu and Fang Song and Penghui Yao},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_297,
title = {A Faster Algorithm for the Free Energy in One-Dimensional Quantum Systems},
author = {Samuel Scalet},
url = {https://arxiv.org/abs/2402.19030},
year = {2024},
date = {2024-01-01},
abstract = {We consider the problem of approximating the free energy density of a translation-invariant, one-dimensional quantum spin system with finite range. While the complexity of this problem is nontrivial due to its close connection to problems with known hardness results, a classical subpolynomial-time algorithm has recently been proposed [Fawzi et al., 2022]. Combining several algorithmic techniques previously used for related problems, we propose an algorithm outperforming this result asymptotically and give rigorous bounds on its runtime. Our main techniques are the use of Araki expansionals, known from results on the nonexistence of phase transitions, and a matrix product operator construction. We also review a related approach using the Quantum Belief Propagation [Kuwahara et al., 2018], which in combination with our findings yields an equivalent result.},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
We consider the problem of approximating the free energy density of a translation-invariant, one-dimensional quantum spin system with finite range. While the complexity of this problem is nontrivial due to its close connection to problems with known hardness results, a classical subpolynomial-time algorithm has recently been proposed [Fawzi et al., 2022]. Combining several algorithmic techniques previously used for related problems, we propose an algorithm outperforming this result asymptotically and give rigorous bounds on its runtime. Our main techniques are the use of Araki expansionals, known from results on the nonexistence of phase transitions, and a matrix product operator construction. We also review a related approach using the Quantum Belief Propagation [Kuwahara et al., 2018], which in combination with our findings yields an equivalent result.
@Poster{P24_416,
title = {A framework of partial error correction for intermediate-scale quantum computers},
author = {Nikolaos Koukoulekidis and Samson Wang and Tom O'Leary and Daniel Bultrini and Lukasz Cincio and Piotr Czarnik},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_506,
title = {A general purification protocol with imperfect state preparation},
author = {Golshan Lirabi and Faedi Loulidi and David Elkouss},
year = {2024},
date = {2024-01-01},
abstract = {Purification protocols take several copies of a
mixed state and output a smaller number of copies with
higher purity. Recently, a protocol based on the Swap test
was shown to have optimal resource consumption, with
the number of samples scaling proportional to the inverse
of the error. In this work, we consider a more realistic
scenario in which all the prepared states are noisy,
including the auxiliary qubits used by the protocol. Here,
we show that this generalization does not compromise
convergence, with the protocol still converging for all non
extreme noise values. Moreover, we estimate the number
of iterations and resources needed in the generalized
scenario. Such an estimation allows us to address the
optimality of the protocol with noisy state preparation and show that the protocol is no longer optimal.},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
Purification protocols take several copies of a
mixed state and output a smaller number of copies with
higher purity. Recently, a protocol based on the Swap test
was shown to have optimal resource consumption, with
the number of samples scaling proportional to the inverse
of the error. In this work, we consider a more realistic
scenario in which all the prepared states are noisy,
including the auxiliary qubits used by the protocol. Here,
we show that this generalization does not compromise
convergence, with the protocol still converging for all non
extreme noise values. Moreover, we estimate the number
of iterations and resources needed in the generalized
scenario. Such an estimation allows us to address the
optimality of the protocol with noisy state preparation and show that the protocol is no longer optimal.
@Poster{P24_322,
title = {A Max-Flow approach to Random Tensor Networks},
author = {Faedi Loulidi and Khurshed Fitter and Ion Nechita},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_291,
title = {A Note on Exponential Quantum One-Wayness},
author = {Giulio Malavolta and Tomoyuki Morimae and Michael Walter and Takashi Yamakawa},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_524,
title = {A Practical Protocol for Quantum Oblivious Transfer from One-Way Functions},
author = {Eleni Diamanti and Alex Bredariol Grilo and Adriano Innocenzi and Pascal Lefebvre and Verena Yacoub and Alvaro Yángüez},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_512,
title = {A pure (2+1)-dimensional SU(2) model for analog simulation in small-scale superconducting quantum devices},
author = {Lucia Valor and Klaus Liegener and Stefan Filipp and Peter Rabl},
year = {2024},
date = {2024-01-01},
abstract = {Lattice gauge theories constitute an important tool in studying the fundamental interactions of matter within particle physics and have a wide range of applications in condensed matter physics and quantum information theory. While classical numerical methods can be used to simulate many properties of Abelian and non-Abelian gauge theories efficiently, the intrinsic quantum nature of these theories makes other relevant physical phenomena hard to reproduce. Quantum simulators offer a promising approach to address these challenges, with successful simulations of Abelian theories in different quantum platforms demonstrating their potential in the last decades. Despite these advances, quantum simulation of non-Abelian theories remains challenging. Recent research efforts aimed at the analog simulation of these gauge theories have predominantly focused on atomic quantum platforms like ultracold atoms and trapped ions. Here, we propose a minimal model for a (2+1)-dimensional pure SU(2) lattice gauge theory, implementable as an analog simulation on superconducting quantum hardware. We study properties of the system, such as the effect of adding bosonic excitations, and explore its experimental implementation. Our work contributes to the exploration and understanding of non-Abelian gauge theories and offers a new and rich implementation to study lattice gauge theories using superconducting qubits.},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
Lattice gauge theories constitute an important tool in studying the fundamental interactions of matter within particle physics and have a wide range of applications in condensed matter physics and quantum information theory. While classical numerical methods can be used to simulate many properties of Abelian and non-Abelian gauge theories efficiently, the intrinsic quantum nature of these theories makes other relevant physical phenomena hard to reproduce. Quantum simulators offer a promising approach to address these challenges, with successful simulations of Abelian theories in different quantum platforms demonstrating their potential in the last decades. Despite these advances, quantum simulation of non-Abelian theories remains challenging. Recent research efforts aimed at the analog simulation of these gauge theories have predominantly focused on atomic quantum platforms like ultracold atoms and trapped ions. Here, we propose a minimal model for a (2+1)-dimensional pure SU(2) lattice gauge theory, implementable as an analog simulation on superconducting quantum hardware. We study properties of the system, such as the effect of adding bosonic excitations, and explore its experimental implementation. Our work contributes to the exploration and understanding of non-Abelian gauge theories and offers a new and rich implementation to study lattice gauge theories using superconducting qubits.
@Poster{P24_412,
title = {A quantum algorithm for the pathfinding problem via the quantum electrical flow},
author = {Jianqiang Li and Sean Hallgren},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_334,
title = {A quasi-polynomial time classical algorithm for almost any noisy quantum circuit},
author = {Thomas Schuster and Norman Y. Yao},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_476,
title = {A Unified Theory of Barren Plateaus for Deep Parametrized Quantum Circuits},
author = {Martin Larocca and Marco Cerezo and Frederic Sauvage and Michael Ragone and Bojko Bakalov and Alexander Kemper and Carlos Ortiz Marrero},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_328,
title = {Accelerated Convergence in Training Quantum Neural Network with Modest Depths},
author = {Kaining Zhang and Junyu Liu and Liu Liu and Liang Jiang and Min-Hsiu Hsieh and Dacheng Tao},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_469,
title = {Activation of post-quantumness in generalized EPR scenarios},
author = {Beata Zjawin and Matty Hoban and Ana Belén Sainz and Paul Skrzypczyk},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_503,
title = {Advances in quantum algorithms for the shortest s-t path problem.},
author = {Adam Wesolowski and Stephen Piddock},
year = {2024},
date = {2024-01-01},
abstract = {We study a fundamental problem in graph theory of finding the shortest path between vertices in
an undirected, weighted graph. We present quantum algorithms in the adjacency array model which for the considered instances show a polynomial separation over the best known classical and quantum algorithms. First of our approaches is based on sampling the quantum flow state in a divide and conquer framework. Our second approach is based on querying the classical shadow of the quantum flow state and following a greedy algorithm. In particular, we show that using O(m) space we can find the shortest path in time that is asymptotically equal to the time required for detecting a path.},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
We study a fundamental problem in graph theory of finding the shortest path between vertices in
an undirected, weighted graph. We present quantum algorithms in the adjacency array model which for the considered instances show a polynomial separation over the best known classical and quantum algorithms. First of our approaches is based on sampling the quantum flow state in a divide and conquer framework. Our second approach is based on querying the classical shadow of the quantum flow state and following a greedy algorithm. In particular, we show that using O(m) space we can find the shortest path in time that is asymptotically equal to the time required for detecting a path.
@Poster{P24_559,
title = {Advantage of Hardy's nonlocal correlation in reverse zero-error channel coding},
author = {Mir Alimuddin and Ananya Chakraborty and Govind Lal Sidhardh and Ram Krishna Patra and Samrat Sen and Sahil Gopalkrishna Naik and Manik Banik},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_441,
title = {Advantage of multi-partite entanglement for quantum cryptography over long and short ranged networks},
author = {Janka Memmen and Jens Eisert and Nathan Walk},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_358,
title = {Æ codes},
author = {Shubham P. Jain and Eric R. Hudson and Wesley C. Campbell and Victor V. Albert},
url = {https://arxiv.org/abs/2311.12324},
year = {2024},
date = {2024-01-01},
abstract = {Diatomic molecular codes [1] are designed to encode quantum information in the orientation of a diatomic molecule, allowing error correction from small torques and changes in angular momentum. In this work, we directly study noise native to atomic and molecular platforms – spontaneous emission, stray electromagnetic fields, and Raman scattering – and show that diatomic molecular codes fail against this noise. I will derive simple necessary and sufficient conditions for codes to protect against such noise. We also identify existing and develop new absorption-emission (Æ) codes that are more practical than molecular codes, require lower average momentum, can directly protect against photonic processes up to arbitrary order, and are applicable to a broader set of atomic and molecular systems. [1] Robust encoding of a qubit in a molecule, Albert V., Covey J., Preskill J., PhysRevX.10.031050, arXiv:1911.00099},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
Diatomic molecular codes [1] are designed to encode quantum information in the orientation of a diatomic molecule, allowing error correction from small torques and changes in angular momentum. In this work, we directly study noise native to atomic and molecular platforms – spontaneous emission, stray electromagnetic fields, and Raman scattering – and show that diatomic molecular codes fail against this noise. I will derive simple necessary and sufficient conditions for codes to protect against such noise. We also identify existing and develop new absorption-emission (Æ) codes that are more practical than molecular codes, require lower average momentum, can directly protect against photonic processes up to arbitrary order, and are applicable to a broader set of atomic and molecular systems. [1] Robust encoding of a qubit in a molecule, Albert V., Covey J., Preskill J., PhysRevX.10.031050, arXiv:1911.00099
@Poster{P24_500,
title = {All you need is Trotter},
author = {Gumaro Rendon},
url = {https://arxiv.org/abs/2311.01533},
year = {2024},
date = {2024-01-01},
abstract = {The work here enables linear cost-scaling with evolution time t while keeping polylog(1/ε) scaling and no extra block-encoding qubits, where ε is the algorithmic error. This is achieved through product formulas, stable interpolation (Chebyshev), and to calculate the needed fractional queries, cardinal sine interpolation is used.},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
The work here enables linear cost-scaling with evolution time t while keeping polylog(1/ε) scaling and no extra block-encoding qubits, where ε is the algorithmic error. This is achieved through product formulas, stable interpolation (Chebyshev), and to calculate the needed fractional queries, cardinal sine interpolation is used.
@Poster{P24_509,
title = {An entanglement distillation-based state estimator},
author = {Joshua Carlo Casapao and Ananda Gopal Maity and Naphan Benchasattabuse and Michal Hajdusek and Rodney Van Meter and David Elkouss},
year = {2024},
date = {2024-01-01},
abstract = {Estimating state parameters given the constraints on experimental effort and resource cost remains a challenge for practical quantum information processing. In this context, we demonstrate that Bell-diagonal parameters of an arbitrary state can be efficiently estimated solely from the measurement statistics of an idealized distillation protocol. Furthermore, we consider estimating those parameters within a more realistic distillation protocol that operates under noise. This novel estimation method is particularly beneficial for scenarios where distillation is an indispensable step.},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
Estimating state parameters given the constraints on experimental effort and resource cost remains a challenge for practical quantum information processing. In this context, we demonstrate that Bell-diagonal parameters of an arbitrary state can be efficiently estimated solely from the measurement statistics of an idealized distillation protocol. Furthermore, we consider estimating those parameters within a more realistic distillation protocol that operates under noise. This novel estimation method is particularly beneficial for scenarios where distillation is an indispensable step.
@Poster{P24_356,
title = {An implementable iterative quantum algorithm for approximating geometric entanglement},
author = {Andrii Semenov and Niall Murphy and Simone Patscheider and Elena Blokhina},
url = {https://arxiv.org/abs/2405.19134},
year = {2024},
date = {2024-01-01},
abstract = {Entanglement is one of the fundamental properties of a quantum state and is a crucial differentiator between classical and quantum computation. There are many ways to define entanglement and its measure, depending on the problem or application under consideration. Each of these measures may be computed or approximated by multiple methods. However, hardly any of these methods can be run on near-term quantum hardware. This work presents a quantum adaptation of the iterative higher-order power method for estimating the geometric measure of entanglement of multi-qubit pure states using rank-1 tensor approximation. This method is executable on current (hybrid) quantum hardware and does not depend on quantum memory. We study the effect of noise on the algorithm using a simple theoretical model based on the standard depolarising channel. This model allows us to post hoc mitigate the effects of noise on the results of the computation.},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
Entanglement is one of the fundamental properties of a quantum state and is a crucial differentiator between classical and quantum computation. There are many ways to define entanglement and its measure, depending on the problem or application under consideration. Each of these measures may be computed or approximated by multiple methods. However, hardly any of these methods can be run on near-term quantum hardware. This work presents a quantum adaptation of the iterative higher-order power method for estimating the geometric measure of entanglement of multi-qubit pure states using rank-1 tensor approximation. This method is executable on current (hybrid) quantum hardware and does not depend on quantum memory. We study the effect of noise on the algorithm using a simple theoretical model based on the standard depolarising channel. This model allows us to post hoc mitigate the effects of noise on the results of the computation.
@Poster{P24_389,
title = {Approximate t-design depths in generic circuit architectures},
author = {Daniel Belkin and James Allen and Soumik Ghosh and Christopher Kang and Sophia Lin and James Sud and Fred Chong and Bill Fefferman and Bryan Clark},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_379,
title = {Arbitrary Polynomial Separations in Trainable Quantum Machine Learning},
author = {Eric Anschuetz and Xun Gao},
url = {https://arxiv.org/abs/2402.08606},
year = {2024},
date = {2024-01-01},
abstract = {Recent theoretical results in quantum machine learning have demonstrated a general trade-off between the expressive power of quantum neural networks (QNNs) and their trainability; as a corollary of these results, practical exponential separations in expressive power over classical machine learning models are believed to be infeasible as such QNNs take a time to train that is exponential in the model size. We here circumvent these negative results by constructing a hierarchy of efficiently trainable QNNs that exhibit unconditionally provable, polynomial memory separations of arbitrary constant degree over classical neural networks in performing a classical sequence modeling task. Furthermore, each unit cell of the introduced class of QNNs is computationally efficient, implementable in constant time on a quantum device. The classical networks we prove a separation over include well-known examples such as recurrent neural networks and Transformers. We show that quantum contextuality is the source of the expressivity separation, suggesting that other classical sequence learning problems with long-time correlations may be a regime where practical advantages in quantum machine learning may exist.},
keywords = {Outstanding Poster, Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
Recent theoretical results in quantum machine learning have demonstrated a general trade-off between the expressive power of quantum neural networks (QNNs) and their trainability; as a corollary of these results, practical exponential separations in expressive power over classical machine learning models are believed to be infeasible as such QNNs take a time to train that is exponential in the model size. We here circumvent these negative results by constructing a hierarchy of efficiently trainable QNNs that exhibit unconditionally provable, polynomial memory separations of arbitrary constant degree over classical neural networks in performing a classical sequence modeling task. Furthermore, each unit cell of the introduced class of QNNs is computationally efficient, implementable in constant time on a quantum device. The classical networks we prove a separation over include well-known examples such as recurrent neural networks and Transformers. We show that quantum contextuality is the source of the expressivity separation, suggesting that other classical sequence learning problems with long-time correlations may be a regime where practical advantages in quantum machine learning may exist.
@Poster{P24_429,
title = {Benchmarking bosonic and fermionic dynamics},
author = {Jadwiga Wilkens and Marios Ioannou and Ellen Derbyshire and Jens Eisert and Dominik Hangleiter and Ingo Roth and Jonas Haferkamp},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_530,
title = {Biased Clifford Classical Shadows Tomography},
author = {Angus Mingare and Timothy Weaving and Peter Coveney},
year = {2024},
date = {2024-01-01},
abstract = {The variational quantum eigensolver (VQE) is a near-term quantum algorithm designed to estimate the groundstate energy of a molecular system. Unfortunately to achieve accurate results VQE requires a prohibitive number of shots, thus far restricting its utility to very small systems. Classical shadows tomography (CST) is a partial tomography scheme that can predict many properties of a quantum system given relatively few measurements. It has been suggested as a solution to the measurement problem in VQE and comes with the additional benefit of "measure now, ask questions later". That is, because CST doesn't need to know a priori which observables we are wanting to estimate, the same measurement results can be recycled to predict arbitrary expectation values. In this work, we develop a biasing scheme for Clifford-measurement CST that can be used to improve the accuracy of expectation value estimations for observables known a priori (such as the groundstate energy) while not sacrificing the ability to predict arbitrary expectation values, something that is lost in biased Pauli-measurement CST schemes. We demonstrate the method by simultaneously measuring the groundstate energy and arbitrary Pauli strings for a range of molecular systems. This work successfully improves Clifford-measurement CST for use within VQE while staying faithful to the core principle of CST.},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
The variational quantum eigensolver (VQE) is a near-term quantum algorithm designed to estimate the groundstate energy of a molecular system. Unfortunately to achieve accurate results VQE requires a prohibitive number of shots, thus far restricting its utility to very small systems. Classical shadows tomography (CST) is a partial tomography scheme that can predict many properties of a quantum system given relatively few measurements. It has been suggested as a solution to the measurement problem in VQE and comes with the additional benefit of "measure now, ask questions later". That is, because CST doesn't need to know a priori which observables we are wanting to estimate, the same measurement results can be recycled to predict arbitrary expectation values. In this work, we develop a biasing scheme for Clifford-measurement CST that can be used to improve the accuracy of expectation value estimations for observables known a priori (such as the groundstate energy) while not sacrificing the ability to predict arbitrary expectation values, something that is lost in biased Pauli-measurement CST schemes. We demonstrate the method by simultaneously measuring the groundstate energy and arbitrary Pauli strings for a range of molecular systems. This work successfully improves Clifford-measurement CST for use within VQE while staying faithful to the core principle of CST.
@Poster{P24_304,
title = {Bosonic randomized benchmarking with passive transformations},
author = {Mirko Arienzo and Martin Kliesch and Markus Heinrich},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
@Poster{P24_456,
title = {Bounding the quantum violation of causal inequalities},
author = {Zixuan Liu and Giulio Chiribella},
year = {2024},
date = {2024-01-01},
keywords = {Poster session Thursday},
pubstate = {published},
tppubtype = {Poster}
}
