The poster session will be on Tuesday afternoon (see schedule). The posters will stay up all week in the Department of Mathematics.

The online poster presentations will take place through dedicated Audio/Video channels on the TQC Discord server. You can present your poster during the poster session or at any other time during the conference; all instructions can be found on the Discord server.

Note that not all accepted posters will be presented at the conference due to author availability constraints. If you cannot present your poster, you don’t need to email us.

Madelyn Cain, Edward Farhi, Sam Gutmann, Daniel Ranard, Eugene Tang

The QAOA gets stuck starting from a good classical string Poster

2023.

@Poster{P7219,

title = {The QAOA gets stuck starting from a good classical string},

author = {Madelyn Cain and Edward Farhi and Sam Gutmann and Daniel Ranard and Eugene Tang},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Edoardo Alessandroni

The quantum big-M problem: optimizing constraints penalization in quadratic binary optimization Poster

2023.

@Poster{P6311,

title = {The quantum big-M problem: optimizing constraints penalization in quadratic binary optimization},

author = {Edoardo Alessandroni},

year = {2023},

date = {2023-01-01},

abstract = {When it is a matter of optimally solving a mathematical optimization problem, quantum optimization has in principle a theoretical advantage over classical optimization. In particular, Quadratic Unconstrained Binary Optimization (QUBO) problems are well suited for quantum solvers, since they are equivalent to an Ising spin model. In order to map a generic combinatorial optimization problem to a QUBO, however, removing the constraints requires selecting a penalty coefficient known in the classical community as "big-M". We show how the problem of selecting a suitable big-M value is daunting when employing quantum solvers as well, while we propose a novel approach to compute an efficient value of it, in order to have a QUBO formulation which is easier to solve. We finally benchmark the proposed method on toy generic instances and on Portfolio Optimization instances, both with simulations and on quantum hardware, showing a clear advantage when using the proposed technique.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

André Chailloux, Jean-Pierre Tillich

The Quantum Decoding Problem Talk

2024.

@Talk{T24_222,

title = {The Quantum Decoding Problem},

author = {André Chailloux and Jean-Pierre Tillich},

year = {2024},

date = {2024-01-01},

abstract = {One of the founding results of lattice based cryptography is a quantum reduction from the Short Integer Solution (SIS) problem to the Learning with Errors (LWE) problem introduced by Regev. It has recently been pointed out by Chen, Liu and Zhandry[CLZ22] that this reduction can be made more powerful by replacing the LWE problem with a quantum equivalent, where the errors are given in quantum superposition. In parallel, Regev's reduction has recently been adapted in the context of code-based cryptography by Debris, Remaud and Tillich[DRT23], who showed a reduction between the Short Codeword Problem and the Decoding Problem (the DRT reduction). This motivates the study of the Quantum Decoding Problem (QDP), which is the Decoding Problem but with errors in quantum superposition and see how it behaves in the DRT reduction. The purpose of this paper is to introduce and to lay a firm foundation for QDP. We first show QD Pis likely to be easier than classical decoding, by proving that it can be solved in quantum polynomial time in a large regime of noise whereas no non-exponential quantum algorithm is known for the classical decoding problem. Then, we show that QDP can even be solved (albeit not necessarily efficiently) beyond the information theoretic Shannon limit for classical decoding. We give precisely the largest noise level where we can solve QDP giving in a sense the information theoretic limit for this new problem. Finally, we study how QDP can be used in the DRT reduction. First, we show that our algorithms can be properly used in the DRT reduction showing that our quantum algorithms for QDP beyond Shannon capacity can be used to find minimal weight codewords in a random code. On the negative side, we show that the DRT reduction cannot be, in all generality, a reduction between finding small codewords and QDP by exhibiting quantum algorithms for QDP where this reduction entirely fails. Our proof techniques include the use of specific quantum measurements, such as q-ary unambiguous state discrimination and pretty good measurements as well as strong concentration bounds on weight distribution of random shifted dual codes, which we relate using quantum Fourier analysis.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Yixian Qiu, Kelvin Koor, Patrick Rebentrost

The Quantum Esscher Transform Talk

2024.

@Talk{T24_431,

title = {The Quantum Esscher Transform},

author = {Yixian Qiu and Kelvin Koor and Patrick Rebentrost},

year = {2024},

date = {2024-01-01},

abstract = {The Esscher Transform is a tool of broad utility in various domains of applied probability. It provides the solution to a constrained minimum relative entropy optimization problem. In this work, we study the generalization of the Esscher Transform to the quantum setting. We examine a relative entropy minimization problem for a quantum density operator, potentially of wide relevance in quantum information theory. The resulting solution form motivates us to define the quantum Esscher Transform, which subsumes the classical Esscher Transform as a special case. Envisioning potential applications of the quantum Esscher Transform, we also discuss its implementation on fault-tolerant quantum computers. Our algorithm is based on the modern techniques of block-encoding and quantum singular value transformation (QSVT). We show that given block-encoded inputs, our algorithm outputs a subnormalized block-encoding of the quantum Esscher transform within accuracy ε in $tilde O(kappa d łog^2 1/epsilon)$ queries to the inputs, where κ is the condition number of the input density operator and $d$ is the number of constraints.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Massimiliano Incudini, Michele Grossi, Antonio Mandarino, Sofia Vallecorsa, Alessandra Di Pierro, David Windridge

The Quantum Path Kernel: a Generalized Quantum Neural Tangent Kernel for Deep Quantum Machine Learning Poster

2023.

@Poster{P4838,

title = {The Quantum Path Kernel: a Generalized Quantum Neural Tangent Kernel for Deep Quantum Machine Learning},

author = {Massimiliano Incudini and Michele Grossi and Antonio Mandarino and Sofia Vallecorsa and Alessandra Di Pierro and David Windridge},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Duyal Yolcu

The R-algebra of quasiknowledge and convex optimization Poster

2023.

@Poster{P2044,

title = {The R-algebra of quasiknowledge and convex optimization},

author = {Duyal Yolcu},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Patrick Rall, Chunhao Wang, Pawel Wocjan

Thermal State Preparation via Rounding Promises Poster

2023.

Abstract | Links:

@Poster{P890,

title = {Thermal State Preparation via Rounding Promises},

author = {Patrick Rall and Chunhao Wang and Pawel Wocjan},

url = {https://arxiv.org/abs/2210.01670},

year = {2023},

date = {2023-01-01},

abstract = {A promising avenue for the preparation of Gibbs states on a quantum computer is to simulate the physical thermalization process. The Davies generator describes the dynamics of an open quantum system that is in contact with a heat bath. Crucially, it does not require simulation of the heat bath itself, only the system we hope to thermalize. Using the state-of-the-art techniques for quantum simulation of the Lindblad equation, we devise a technique for the preparation of Gibbs states via thermalization as specified by the Davies generator. In doing so, we encounter a severe technical challenge: implementation of the Davies generator demands the ability to estimate the energy of the system unambiguously. That is, each energy of the system must be deterministically mapped to a unique estimate. Previous work showed that this is only possible if the system satisfies an unphysical 'rounding promise' assumption. We solve this problem by engineering a random ensemble of rounding promises that simultaneously solves three problems: First, each rounding promise admits preparation of a 'promised' thermal state via a Davies generator. Second, these Davies generators have a similar mixing time as the ideal Davies generator. Third, the average of these promised thermal states approximates the ideal thermal state.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Thomas Theurer, Elia Zanoni, Carlo Maria Scandolo, Gilad Gour

Thermodynamic state convertibility is determined by qubit cooling and heating Poster

2023.

@Poster{P2564,

title = {Thermodynamic state convertibility is determined by qubit cooling and heating},

author = {Thomas Theurer and Elia Zanoni and Carlo Maria Scandolo and Gilad Gour},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Nuriya Nurgalieva, Simon Mathis, Lídia Del Rio, Renato Renner

Thought experiments in a quantum computer Poster

2023.

Abstract | Links:

@Poster{P7418,

title = {Thought experiments in a quantum computer},

author = {Nuriya Nurgalieva and Simon Mathis and Lídia Del Rio and Renato Renner},

url = {https://arxiv.org/abs/2209.06236},

year = {2023},

date = {2023-01-01},

abstract = {We introduce a software package that allows users to design and run simulations of thought experiments in quantum theory. In particular, it covers cases where several reasoning agents are modelled as quantum systems, such as Wigner's friend experiment. Users can customize the protocol of the experiment, the inner workings of agents (including a quantum circuit that models their reasoning process), the abstract logical system used (which may or not allow agents to combine premises and make inferences about each other's reasoning), and the interpretation of quantum theory used by different agents. Our open-source software is written in a quantum programming language, ProjectQ, and runs on classical or quantum hardware. As an example, we model the Frauchiger-Renner extended Wigner's friend thought experiment, where agents are allowed to measure each other's physical memories, and make inferences about each other's reasoning.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Jonas Helsen, Michael Walter

Thrifty shadow estimation: re-using quantum circuits and bounding tails Workshop

2023.

Abstract | Links:

@Workshop{T3723,

title = {Thrifty shadow estimation: re-using quantum circuits and bounding tails},

author = {Jonas Helsen and Michael Walter},

url = {https://arxiv.org/abs/2212.06240},

year = {2023},

date = {2023-01-01},

abstract = {Randomized shadow estimation is a recent protocol that allows estimating exponentially many expectation values of a quantum state from ``classical shadows'', obtained by applying random quantum circuits and computational basis measurements. In this paper we study the statistical efficiency of this approach in light of near-term quantum computing. In particular, we propose and analyze a more practically-implementable variant of the protocol, thrifty shadow estimation, in which quantum circuits are reused many times instead of having to be freshly generated for each measurement (as in the original protocol). We show that the effect of this reuse strongly depends on the family of quantum circuits that is chosen. In particular, it is maximally effective when sampling Haar random unitaries, and maximally ineffective when sampling Clifford circuits (even though the Clifford group forms a three-design). To interpolate between these two extremes, we provide an efficiently simulable family of quantum circuits inspired by a recent construction of approximate t-designs. Finally we consider tail bounds for shadow estimation and discuss when median-of-means estimation can be replaced with standard mean estimation.},

howpublished = {Talk},

keywords = {},

pubstate = {published},

tppubtype = {Workshop}

}

Yingkai Ouyang, Masahito Hayashi

Tight Cramér-Rao type bounds for multiparameter quantum metrology through conic programming Workshop

2023.

Abstract | Links:

@Workshop{T7082,

title = {Tight Cramér-Rao type bounds for multiparameter quantum metrology through conic programming},

author = {Yingkai Ouyang and Masahito Hayashi},

url = {https://arxiv.org/abs/2209.05218},

year = {2023},

date = {2023-01-01},

abstract = {In the quest to unlock the maximum potential of quantum sensors, it is of paramount importance to have practical measurement strategies that can estimate incompatible parameters with best precisions possible. However, it is still not known how to find practical measurements with optimal precisions, even for uncorrelated measurements over probe states. Here, we give a concrete way to find uncorrelated measurement strategies with optimal precisions. We solve this fundamental problem by introducing a framework of conic programming that unifies the theory of precision bounds for multiparameter estimates for uncorrelated and correlated measurement strategies under a common umbrella. Namely, we give precision bounds that arise from linear programs on various cones defined on a tensor product space of matrices, including a particular cone of separable matrices. Subsequently, our theory allows us to develop an efficient algorithm that calculates both upper and lower bounds for the ultimate precision bound for uncorrelated measurement strategies, where these bounds can be tight. In particular, the uncorrelated measurement strategy that arises from our theory saturates the upper bound to the ultimate precision bound. Also, we show numerically that there is a strict gap between the previous efficiently computable bounds and the ultimate precision bound.},

howpublished = {Talk},

keywords = {},

pubstate = {published},

tppubtype = {Workshop}

}

Álvaro Navarrete, Marcos Curty

Tight Security Analysis of Decoy-State Quantum Key Distribution Against Trojan-Horse Attacks Poster

2023.

Abstract | Links:

@Poster{P3177,

title = {Tight Security Analysis of Decoy-State Quantum Key Distribution Against Trojan-Horse Attacks},

author = {Álvaro Navarrete and Marcos Curty},

url = {https://iopscience.iop.org/article/10.1088/2058-9565/ac74dc/meta},

year = {2023},

date = {2023-01-01},

abstract = {Most security proofs of quantum key distribution (QKD) disregard the effect of information leakage from the users’ devices, and, thus, do not protect against Trojan-horse attacks (THAs). In a THA, the eavesdropper injects strong light into the QKD apparatuses, and then analyzes the back-reflected light to learn information about their internal setting choices. Only a few works consider this security threat but predict a rather poor performance of QKD unless the devices are strongly isolated from the channel. Here, we derive finite-key security bounds for decoy-state-based QKD schemes in the presence of THAs, which significantly outperform previous analyses.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Samrat Sen, Edwin Peter Lobo, Ram Krishna Patra, Sahil Gopalkrishna Naik, Anandamay Das Bhowmik, Mir Alimuddin, Manik Banik

Timelike correlations and quantum tensor product structure Poster

2023.

@Poster{P5886,

title = {Timelike correlations and quantum tensor product structure},

author = {Samrat Sen and Edwin Peter Lobo and Ram Krishna Patra and Sahil Gopalkrishna Naik and Anandamay Das Bhowmik and Mir Alimuddin and Manik Banik},

url = {https://tqc-conference.org/wp-content/uploads/cfdb7_uploads/1688131797-video-video.mp4},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Tan Van Vu, Keiji Saito

Topological speed limit Poster

2023.

@Poster{P4786,

title = {Topological speed limit},

author = {Tan Van Vu and Keiji Saito},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Noah Berthusen, Dhruv Devulapalli, Eddie Schoute, Andrew Childs, Michael Gullans, Alexey Gorshkov, Daniel Gottesman

Toward a 2D Local Implementation of Quantum LDPC Codes Talk

2024.

@Talk{T24_373,

title = {Toward a 2D Local Implementation of Quantum LDPC Codes},

author = {Noah Berthusen and Dhruv Devulapalli and Eddie Schoute and Andrew Childs and Michael Gullans and Alexey Gorshkov and Daniel Gottesman},

year = {2024},

date = {2024-01-01},

abstract = {Geometric locality is an important theoretical and practical factor for quantum low-density parity-check (qLDPC) codes which affects code performance and ease of physical realization. For device architectures restricted to 2D local gates, naively implementing the high-rate codes suitable for low-overhead fault-tolerant quantum computing incurs prohibitive amounts of overhead. In this work, we present an error correction protocol built on a bilayer architecture that aims to reduce operational overheads when restricted to 2D local gates by measuring some generators less frequently than others. We investigate the family of quasi-cyclic qLDPC codes and show that they are well suited for a parallel syndrome measurement scheme using fast local operations and classical communication (LOCC) routing. Through circuit-level simulations, we find that in some parameter regimes quasi-cyclic codes implemented with this protocol have logical error rates comparable to copies of the surface codes while using fewer physical qubits.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Ariel Bendersky

Towards algorithmic proofs of maximal MUB sets in arbitrary integer dimension Poster

2023.

@Poster{P1627,

title = {Towards algorithmic proofs of maximal MUB sets in arbitrary integer dimension},

author = {Ariel Bendersky},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Laura Clinton, Toby Cubitt, Brian Flynn, Filippo Maria Gambetta, Joel Klassen, Ashley Montanaro, Stephen Piddock, Raul A. Santos, Evan Sheridan

Towards near-term quantum simulation of materials Workshop

2023.

@Workshop{T8983,

title = {Towards near-term quantum simulation of materials},

author = {Laura Clinton and Toby Cubitt and Brian Flynn and Filippo Maria Gambetta and Joel Klassen and Ashley Montanaro and Stephen Piddock and Raul A. Santos and Evan Sheridan},

year = {2023},

date = {2023-01-01},

abstract = {The limiting constraint on simulating materials on near-term quantum hardware is the requisite circuit depths and qubit numbers, with current estimates placing them well beyond near-term capabilities. A critical subroutine of simulation algorithms is implementing a layer of unitary evolutions by each local term in the Hamiltonian. In this work we develop a new quantum algorithm which dramatically reduces the estimated cost of material simulations using this subroutine, improving circuit depths by up to 6 orders of magnitude for Strontium Vanadate, for example. We achieve this by introducing a fermionic encoding that leverages the locality of materials Hamiltonians describing an active space in the Wannier basis. This design generates quantum circuits whose depth is independent of the system’s size.},

howpublished = {Talk},

keywords = {},

pubstate = {published},

tppubtype = {Workshop}

}

Charles Yuan, Michael Carbin

Tower: Data Structures in Quantum Superposition Poster

2023.

@Poster{P1735,

title = {Tower: Data Structures in Quantum Superposition},

author = {Charles Yuan and Michael Carbin},

year = {2023},

date = {2023-01-01},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Ladina Hausmann, Nuriya Nurgalieva, Lídia Rio

Toys can’t play: modelling physical agents in Spekkens’ theory Poster

2023.

@Poster{P9603,

title = {Toys can’t play: modelling physical agents in Spekkens’ theory},

author = {Ladina Hausmann and Nuriya Nurgalieva and Lídia Rio},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Junqiao Lin

Tracial embeddable strategies: Lifting MIP* tricks to MIPco Talk

2024.

@Talk{T24_130,

title = {Tracial embeddable strategies: Lifting MIP* tricks to MIPco},

author = {Junqiao Lin},

year = {2024},

date = {2024-01-01},

abstract = {We prove that any two-party correlation in the commuting operator model can be approximated using a tracial embeddable strategy, a class of strategy defined on a finite tracial von Neumann algebra, which we define in this paper. Using this characterization, we show that any approximately synchronous correlation can be approximated to the average of a collection of synchronous correlations in the commuting operator model. This generalizes the result from Vidick [JMP 2022] which only applies to finite-dimensional quantum correlations. As a corollary, we show that the quantum tensor code test from Ji et al. [FOCS 2022] follows the soundness property even under the general commuting operator model. Furthermore, we extend the state-dependent norm variant of the Gowers-Hatami theorem to finite von Neumann algebras. Combined with the aforementioned characterization, this enables us to lift many known results about robust self-testing for non-local games to the commuting operator model, including a sample efficient finite-dimensional EPR testing for the commuting operator strategies. We believe that, in addition to the contribution from this paper, this class of strategies can be helpful for further understanding non-local games in the infinite-dimensional setting.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Adam Wills, Ting-Chun Lin, Min-Hsiu Hsieh

Tradeoff Constructions for Quantum Locally Testable Codes Talk

2024.

@Talk{T24_15,

title = {Tradeoff Constructions for Quantum Locally Testable Codes},

author = {Adam Wills and Ting-Chun Lin and Min-Hsiu Hsieh},

year = {2024},

date = {2024-01-01},

abstract = {In this work, we continue the search for quantum locally testable codes (qLTCs) of new parameters by presenting three constructions that can make new qLTCs from old. The first analyses the soundness of a quantum code under Hastings' weight reduction construction for qLDPC codes to give a weight reduction procedure for qLTCs. Secondly, we describe a novel `soundness amplification' procedure for qLTCs which can increase the soundness of any qLTC to a constant while preserving its distance and dimension, with an impact only felt on its locality. Finally, we apply the AEL distance amplification construction to the case of qLTCs for the first time which can turn a high-distance qLTC into one with linear distance, at the expense of other parameters. These constructions can be used on as-yet undiscovered qLTCs to obtain new parameters, but we also find a number of present applications to prove the existence of codes in previously unknown parameter regimes. In particular, applications of these operations to the hypersphere product code and the hemicubic code yield many previously unknown parameters. Additionally, soundness amplification can be used to produce the first asymptotically good testable quantum code (rather than locally testable) - that being one with linear distance and dimension, as well as constant soundness. Lastly, applications of all three results are described to an upcoming work.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Ravi Kunjwal, Ämin Baumeler

Trading causal order for locality Poster

2023.

Abstract | Links:

@Poster{P4655,

title = {Trading causal order for locality},

author = {Ravi Kunjwal and Ämin Baumeler},

url = {https://arxiv.org/abs/2202.00440},

year = {2023},

date = {2023-01-01},

abstract = {I'll present some recent work on an intimate link between two a priori distinct phenomena: quantum nonlocality without entanglement and classically-achievable indefinite causal order. The first phenomenon refers to a multipartite scenario where the parties are unable to perfectly discriminate orthogonal product states drawn from an ensemble of quantum states by using local operations and classical communication (LOCC). The second (hypothetical) phenomenon refers to a multipartite scenario where the parties can communicate classically but the local operations of each party are in the future of the other parties, i.e., they cannot be ordered causally. Specifically, we show how three separated parties with access to a classical process exhibiting indefinite causal order—the AF/BW process—can perfectly discriminate the states in an ensemble—the SHIFT ensemble—that exhibits quantum nonlocality without entanglement. I will also mention a generalisation of this result beyond the tripartite case and comment on its connection with separable operations that are outside LOCC. Based on joint work with Ämin Baumeler, arXiv:2202.00440.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Filippo Girardi, Giacomo De Palma

Trained quantum neural networks are Gaussian processes Talk

2024.

@Talk{T24_59,

title = {Trained quantum neural networks are Gaussian processes},

author = {Filippo Girardi and Giacomo De Palma},

year = {2024},

date = {2024-01-01},

abstract = {We study quantum neural networks made by parametric one-qubit gates and fixed two-qubit gates in the limit of infinite width, where the generated function is the expectation value of the sum of single-qubit observables over all the qubits. First, we prove that the probability distribution of the function generated by the untrained network with randomly initialized parameters converges in distribution to a Gaussian process whenever each measured qubit is correlated only with few other measured qubits. Then, we analytically characterize the training of the network via gradient descent with square loss on supervised learning problems. We prove that, as long as the network is not affected by barren plateaus, the trained network can perfectly fit the training set and that the probability distribution of the function generated after training still converges in distribution to a Gaussian process. Finally, we consider the statistical noise of the measurement at the output of the network and prove that a polynomial number of measurements is sufficient for all the previous results to hold and that the network can always be trained in polynomial time.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Vjosa Blakaj, Chokri Manai

Transcendental properties of entropy-constrained sets: Part II Poster

2023.

@Poster{P7607,

title = {Transcendental properties of entropy-constrained sets: Part II},

author = {Vjosa Blakaj and Chokri Manai},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Nitica Sakharwade, Michał Studziński, Michał Eckstein, Paweł Horodecki

Two instances of random access code in the quantum regime Poster

2023.

Abstract | Links:

@Poster{P2788,

title = {Two instances of random access code in the quantum regime},

author = {Nitica Sakharwade and Michał Studziński and Michał Eckstein and Paweł Horodecki},

url = {https://arxiv.org/abs/2208.14422 https://iopscience.iop.org/article/10.1088/1367-2630/acd716},

year = {2023},

date = {2023-01-01},

abstract = {We consider two classes of quantum generalisations of Random Access Code (RAC) and study lower bounds for probabilities of success for such tasks. It provides a useful framework for studying certain information-processing tasks with constrained resources. The first class is based on a random access code with quantum inputs and output known as No-Signalling Quantum RAC (NS-QRAC) [A. Grudka et al. Phys. Rev. A 92, 052312 (2015)], where unbounded entanglement and constrained classical communication are allowed, which can be seen as quantum teleportation with constrained classical communication, for which we provide a quantum lower bound. We consider two modifications to the NS-QRAC scenario, first where unbounded entanglement and constrained quantum communication is allowed and, second where bounded entanglement and unconstrained classical communication are allowed, where we find a monogamy relation for the transmission fidelities, which – in contrast to the usual communication schemes – involves multiple senders and a single receiver. We provide lower bounds for these scenarios. The second class is based on a random access code with a quantum channel and shared entanglement [A. Tavakoli et al. PRX Quantum 2 (4) 040357 (2021)]. We study the set of tasks where two inputs made of two digits of d-base are encoded over a qudit and a maximally entangled state, which can be seen as quantum dense coding with constrained quantum communication, for which we provide quantum lower bounds for d=2,3,4. The encoding employed utilises Gray codes.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Luna Lima E Silva, Daniel Jost Brod

Two interacting particles scattering on a line Poster

2023.

@Poster{P2636,

title = {Two interacting particles scattering on a line},

author = {Luna Lima E Silva and Daniel Jost Brod},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Kieran Mastel, William Slofstra

Two prover perfect zero knowledge for MIP* Talk

2024.

@Talk{T24_139,

title = {Two prover perfect zero knowledge for MIP*},

author = {Kieran Mastel and William Slofstra},

year = {2024},

date = {2024-01-01},

abstract = {The recent MIP*=RE theorem of Ji, Natarajan, Vidick, Wright, and Yuen shows that the complexity class MIP* of multiprover proof systems with entangled provers contains all recursively enumerable languages. Prior work of Grilo, Slofstra, and Yuen [FOCS '19] further shows (via a technique called simulatable codes) that every language in MIP* has a perfect zero knowledge (PZK) MIP* protocol. The MIP*=RE theorem uses two-prover one-round proof systems, and hence such systems are complete for MIP*. However, the construction in Grilo, Slofstra, and Yuen uses six provers, and there is no obvious way to get perfect zero knowledge with two provers via simulatable codes. This leads to a natural question: are there two-prover PZK MIP* protocols for all of MIP*? In this paper, we show that every language in MIP* has a two-prover one-round PZK MIP* protocol, answering the question in the affirmative. For the proof, we use a new method based on a key consequence of the MIP*=RE theorem, which is that every MIP* protocol can be turned into a family of boolean constraint system (BCS) nonlocal games. This makes it possible to work with MIP* protocols as boolean constraint systems, and in particular allows us to use a variant of a construction due to Dwork, Feige, Kilian, Naor, and Safra [Crypto '92] which gives a classical MIP protocol for 3SAT with perfect zero knowledge. To show quantum soundness of this classical construction, we develop a toolkit for analyzing quantum soundness of reductions between BCS games, which we expect to be useful more broadly. This toolkit also applies to commuting operator strategies, and our argument shows that every language with a commuting operator BCS protocol has a two prover PZK commuting operator protocol.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Xiao-Ming Zhang, Zixuan Huo, Kecheng Liu, Ying Li, Xiao Yuan

Unbiased Random Circuit Compiler for Time-Dependent Hamiltonian Simulation Poster

2023.

Abstract | Links:

@Poster{P1092,

title = {Unbiased Random Circuit Compiler for Time-Dependent Hamiltonian Simulation},

author = {Xiao-Ming Zhang and Zixuan Huo and Kecheng Liu and Ying Li and Xiao Yuan},

url = {https://arxiv.org/abs/2212.09445},

year = {2023},

date = {2023-01-01},

abstract = {Pseudorandom quantum states generators (PRSGs) are efficient quantum algorithms that output quantum states which are computationally indistinguishable from Haar random states.

It is known that some computational assumptions are necessary for the existence of PRSGs which output more than $latex łog łambda$-qubit states for the security parameter $latex łambda$. We show that $latex mathbfBQP neq mathbfQCMA$ is necessary for PRSGs with output length $latex n(łambda)$ satisfying $latex n(łambda)=O(łog łambda)$ and $latex n(łambda)gełog łambda$.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

It is known that some computational assumptions are necessary for the existence of PRSGs which output more than $latex łog łambda$-qubit states for the security parameter $latex łambda$. We show that $latex mathbfBQP neq mathbfQCMA$ is necessary for PRSGs with output length $latex n(łambda)$ satisfying $latex n(łambda)=O(łog łambda)$ and $latex n(łambda)gełog łambda$.

Alper Çakan, Vipul Goyal, Chen-Da Liu-Zhang, João Ribeiro

Unbounded Leakage-Resilience and Intrusion-Detection in a Quantum World Talk

2024.

@Talk{T24_263,

title = {Unbounded Leakage-Resilience and Intrusion-Detection in a Quantum World},

author = {Alper Çakan and Vipul Goyal and Chen-Da Liu-Zhang and João Ribeiro},

year = {2024},

date = {2024-01-01},

abstract = {Can an adversary hack into our computer and steal sensitive data such as cryptographic keys? This question is almost as old as the Internet and significant effort has been spent on designing mechanisms to prevent and detect hacking attacks. Once quantum computers arrive, will the situation remain the same or can we hope to live in a better world? We first consider ubiquitous side-channel attacks, which aim to leak side information on secret system components, studied in the leakage-resilient cryptography literature. Classical leakage-resilient cryptography must necessarily impose restrictions on the type of leakage one aims to protect against. As a notable example, the most well-studied leakage model is that of bounded leakage, where it is assumed that an adversary learns at most L bits of leakage on secret components, for some leakage bound L. Although this leakage bound is necessary, many real-world side-channel attacks cannot be captured by bounded leakage. In this work, we design cryptographic schemes that provide guarantees against arbitrary side-channel attacks: - Using techniques from unclonable quantum cryptography, we design several basic leakage-resilient primitives, such as public- and private-key encryption, (weak) pseudorandom functions, and digital signatures which remain secure under (polynomially) unbounded classical leakage. In particular, this leakage can be much longer than the (quantum) secret being leaked upon. In our view, leakage is the result of observations of quantities such as power consumption and hence is most naturally viewed as classical information. Notably, the leakage-resilience of our schemes holds even in the stronger ``LOCC leakage'' model where the adversary can obtain adaptive leakage for (polynomially) emphunbounded number of rounds. - What if the adversary simply breaks in and obtains unbounded quantum leakage (thus making leakage-resilience impossible)? Going beyond leakage, what if the adversary can even tamper with the data arbitrarily? We initiate the study of intrusion-detection in the quantum setting, where one would like to detect if security has been compromised even in the face of an arbitrary intruder attack which can leak and tamper with classical as well as quantum data. We design cryptographic schemes supporting intrusion detection for a host of primitives such as public- and private-key encryption, digital signature, functional encryption, program obfuscation and software protection. Our schemes are based on techniques from cryptography with secure key leasing and certified deletion.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Sumit Rout, Nitica Sakharwade, Some Sankar Bhattacharya, Ravishankar Ramanathan, Pawel Horodecki

Unbounded Quantum Advantage in One-Way Strong Communication Complexity of a Distributed Clique Labelling Relation Poster

2023.

@Poster{P2932,

title = {Unbounded Quantum Advantage in One-Way Strong Communication Complexity of a Distributed Clique Labelling Relation},

author = {Sumit Rout and Nitica Sakharwade and Some Sankar Bhattacharya and Ravishankar Ramanathan and Pawel Horodecki},

year = {2023},

date = {2023-01-01},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Or Sattath, Shai Wyborski

Uncloneable Decryptors from Quantum Copy-Protection Poster

2023.

@Poster{P9282,

title = {Uncloneable Decryptors from Quantum Copy-Protection},

author = {Or Sattath and Shai Wyborski},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Tatsuki Odake, Hlér Kristjánsson, Akihito Soeda, Mio Murao

Universal algorithm for linear transformations of Hamiltonian dynamics Poster

2023.

@Poster{P9097,

title = {Universal algorithm for linear transformations of Hamiltonian dynamics},

author = {Tatsuki Odake and Hlér Kristjánsson and Akihito Soeda and Mio Murao},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Zhenhuan Liu, Chao Yin

Universal Entanglement and Correlation Measure in Two-dimensional Conformal Field Theory Poster

2023.

@Poster{P5766,

title = {Universal Entanglement and Correlation Measure in Two-dimensional Conformal Field Theory},

author = {Zhenhuan Liu and Chao Yin},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Stefano Chessa, Abhijith Jayakumar, Andrey Lokhov, Sidhant Misra

Universal framework for simultaneous tomography of quantum states and SPAM noise Poster

2023.

@Poster{P7636,

title = {Universal framework for simultaneous tomography of quantum states and SPAM noise},

author = {Stefano Chessa and Abhijith Jayakumar and Andrey Lokhov and Sidhant Misra},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Ryuji Takagi, Hiroyasu Tajima, Mile Gu

Universal sampling lower bounds for quantum error mitigation Poster

2023.

@Poster{P8088,

title = {Universal sampling lower bounds for quantum error mitigation},

author = {Ryuji Takagi and Hiroyasu Tajima and Mile Gu},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Hiroyasu Tajima, Ryuji Takagi, Yui Kuramochi, Keiji Saito

Universal trade-off structure between symmetry, irreversibility and quantum coherence for quantum processes Poster

2023.

@Poster{P9784,

title = {Universal trade-off structure between symmetry, irreversibility and quantum coherence for quantum processes},

author = {Hiroyasu Tajima and Ryuji Takagi and Yui Kuramochi and Keiji Saito},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Satoshi Yoshida, Akihito Soeda, Mio Murao

Universal, deterministic, and exact protocol to reverse qubit-unitary and qubit-encoding isometry operations Workshop

2023.

Abstract | Links:

@Workshop{T1434,

title = {Universal, deterministic, and exact protocol to reverse qubit-unitary and qubit-encoding isometry operations},

author = {Satoshi Yoshida and Akihito Soeda and Mio Murao},

url = {https://arxiv.org/abs/2209.02907},

year = {2023},

date = {2023-01-01},

abstract = {In this work, we report a deterministic and exact protocol to reverse any unknown qubit-unitary and qubit-encoding isometry operations. We present the semidefinite programming (SDP) to search the Choi matrix representing a quantum circuit reversing any unitary operation. We derive a quantum circuit transforming four calls of any qubit-unitary operation into its inverse operation by imposing the SU(2)×SU(2) symmetry on the Choi matrix. This protocol only applies only for qubit-unitary operations, but we extend this protocol to any qubit-encoding isometry operations. For that, we derive a subroutine to transform a unitary inversion protocol to an isometry inversion protocol by constructing a quantum circuit transforming finite sequential calls of any isometry operation into random unitary operations.},

howpublished = {Talk},

keywords = {},

pubstate = {published},

tppubtype = {Workshop}

}

Thi Ha Kyaw, Micheline Soley, Brandon Allen, Paul Bergold, Chong Sun, Victor Batista, Alán Aspuru-Guzik

Variational quantum iterative power algorithms for global optimization Poster

2023.

Abstract | Links:

@Poster{P4565,

title = {Variational quantum iterative power algorithms for global optimization},

author = {Thi Ha Kyaw and Micheline Soley and Brandon Allen and Paul Bergold and Chong Sun and Victor Batista and Alán Aspuru-Guzik},

url = {https://arxiv.org/abs/2208.10470 https://tqc-conference.org/wp-content/uploads/cfdb7_uploads/1687744980-poster-4565.pdf},

year = {2023},

date = {2023-01-01},

abstract = {We introduce a family of variational quantum algorithms called quantum iterative power algorithms (QIPA) that outperform existing hybrid near-term quantum algorithms of the same kind. We demonstrate the capabilities of QIPA as applied to three different global-optimization numerical experiments: the ground-state optimization of hydrogen molecular dissociation, search of the transmon qubit ground-state, and biprime factorization. Since our algorithm is hybrid, quantum/classical technologies such as error mitigation and adaptive variational ansatzes can easily be incorporated into the algorithm. Due to the shallow quantum circuit requirements, we anticipate large-scale implementation and adoption of the proposed algorithm across current major quantum hardware.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

Zhenhuan Liu, Xingjian Zhang, Yue-Yang Fei, Zhenyu Cai

Virtual Channel Purification Talk

2024.

@Talk{T24_316,

title = {Virtual Channel Purification},

author = {Zhenhuan Liu and Xingjian Zhang and Yue-Yang Fei and Zhenyu Cai},

year = {2024},

date = {2024-01-01},

abstract = {Quantum error mitigation is a key approach for extracting target state properties on state-of-the-art noisy machines and early fault-tolerant devices. Using the ideas from flag fault tolerance and virtual state purification, we develop the virtual channel purification (VCP) protocol, which consumes similar qubit and gate resources as virtual state purification but offers up to exponentially stronger error suppression with increased system size and more noisy operation copies. Furthermore, VCP removes most of the assumptions required in virtual state purification. Essentially, VCP is the first quantum error mitigation protocol that does not require specific knowledge about the noise models, the target quantum state, and the target problem while still offering rigorous performance guarantees for practical noise regimes. Further connections are made between VCP and quantum error correction to produce one of the first protocols that combine quantum error correction and quantum error mitigation beyond concatenation. We can remove all noise in the channel while paying only the same sampling cost as low-order purification, reaching beyond the standard bias-variance trade-off in quantum error mitigation. Our protocol can also be adapted to key tasks in quantum networks like channel capacity activation and entanglement distribution.},

keywords = {},

pubstate = {published},

tppubtype = {Talk}

}

Xiao Yuan, Bartosz Regula, Ryuji Takagi, Mile Gu

Virtual resource distillation Poster

2023.

@Poster{P2890,

title = {Virtual resource distillation},

author = {Xiao Yuan and Bartosz Regula and Ryuji Takagi and Mile Gu},

year = {2023},

date = {2023-01-01},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}

David Lyons, Cristina Mullican, Adam Rilatt, Jack Putnam

Werner states from diagrams Poster

2023.

Abstract | Links:

@Poster{P7036,

title = {Werner states from diagrams},

author = {David Lyons and Cristina Mullican and Adam Rilatt and Jack Putnam},

url = {https://arxiv.org/abs/2302.05572 https://tqc-conference.org/wp-content/uploads/cfdb7_uploads/1683727419-poster-lyons_tqc2023_poster.pdf},

year = {2023},

date = {2023-01-01},

abstract = {We present two results on multiqubit Werner states, defined to be those states that are invariant under the collective action of any given single-qubit unitary that acts simultaneously on all the qubits. Motivated by the desire to characterize entanglement properties of Werner states, we construct a basis for the real linear vector space of Werner invariant Hermitian operators on the Hilbert space of pure states; it follows that any mixed Werner state can be written as a mixture of these basis operators with unique coefficients. Continuing a study of "polygon diagram" Werner states constructed in earlier work, with a goal to connect diagrams to entanglement properties, we consider a family of multiqubit states that generalize the singlet, and show that their 2-qubit reduced density matrices are separable.},

howpublished = {Poster},

keywords = {},

pubstate = {published},

tppubtype = {Poster}

}