Certified Randomness from a Trapped-Ion Quantum Processor

Abstract: Recently, an experiment using a quantum processor realized a protocol for ‘Certified Randomness’, generating remotely verifiable randomness appealing for applications involving mutually untrusting parties. This protocol builds on the success of pushing the ability of quantum computers to perform beyond-classical computational tasks and leverages the classical hardness of sampling from random quantum circuits to certify 70 kbits of entropy against a realistic adversary using best-known attacks.

Certified Randomness from a Trapped-Ion Quantum Processor

Recently, an experiment using a quantum processor realized a protocol for ‘Certified Randomness’, generating remotely verifiable randomness appealing for applications involving mutually untrusting parties. This protocol builds on the success of pushing the ability of quantum computers to perform beyond-classical computational tasks and leverages the classical hardness of sampling from random quantum circuits to certify 70 kbits of entropy against a realistic adversary using best-known attacks.

Error-corrected fermionic quantum processors with neutral atoms

Abstract: Many-body fermionic systems can be simulated in a hardware-efficient manner using a fermionic quantum processor. Neutral atoms trapped in optical potentials can realize such processors, where non-local fermionic statistics are guaranteed at the hardware level. Implementing quantum error correction in this setup is however challenging, due to the atom-number superselection present in atomic systems, that is, the impossibility of creating coherent superpositions of different particle numbers.

Lost, but not forgotten: Extracting quantum information in noisy systems

Abstract: In this talk, we will mainly focus on noisy quantum trees: at each node of a tree, a received qubit unitarily interacts with fresh ancilla qubits, after which each qubit is sent through a noisy channel to a different node in the next level. Therefore, as the tree depth grows, there is a competition between the irreversible effect of noise and the protection against such noise achieved by delocalization of information.

Lost, but not forgotten: Extracting quantum information in noisy systems

In this talk, we will mainly focus on noisy quantum trees: at each node of a tree, a received qubit unitarily interacts with fresh ancilla qubits, after which each qubit is sent through a noisy channel to a different node in the next level. Therefore, as the tree depth grows, there is a competition between the irreversible effect of noise and the protection against such noise achieved by delocalization of information.

Error-corrected fermionic quantum processors with neutral atoms

Many-body fermionic systems can be simulated in a hardware-efficient manner using a fermionic quantum processor. Neutral atoms trapped in optical potentials can realize such processors, where non-local fermionic statistics are guaranteed at the hardware level. Implementing quantum error correction in this setup is however challenging, due to the atom-number superselection present in atomic systems, that is, the impossibility of creating coherent superpositions of different particle numbers.

Topological stabilizer models on continuous variables

Abstract: In [1] we constructed a family of two-dimensional topological stabilizer codes on continuous variable (CV) degrees of freedom, which generalize homological rotor codes and the toric-GKP code. Our topological codes are built using the concept of boson condensation -- we start from a parent stabilizer code based on an R gauge theory and condense various bosonic excitations.

Topological stabilizer models on continuous variables

In [1] we constructed a family of two-dimensional topological stabilizer codes on continuous variable (CV) degrees of freedom, which generalize homological rotor codes and the toric-GKP code. Our topological codes are built using the concept of boson condensation -- we start from a parent stabilizer code based on an R gauge theory and condense various bosonic excitations. This produces a large class of topological CV stabilizer codes, including ones that are characterized by the anyon theories of U(1)2n×U(1)−2m Chern-Simons theories, for arbitrary pairs of positive integers (n,m).

Conditional lower bounds for algorithms with pre-processed advice

Abstract: Unlike the traditional study of algorithms which attempts to solve a certain task using minimal space and time resources, I will discuss data structures to solve certain algorithmic tasks after an initial pre-processing phase. The interest here is to study the tradeoffs between the resources such as the space and time required to perform the algorithmic task when asked a query; and the resources in the pre-processing phase such as the time required to prepare the data structure or its size.

Universal Adapters between quantum LDPC codes

Abstract: Error-correction is key to building a quantum computer. This includes both storage of quantum information as well as computing on it. Quantum low- density parity check (LDPC) codes offer a route to build these devices with low space overhead. The next question is - how do we fault-tolerantly com- pute on these codes?  Existing proposals (Cohen et al. [2110.10794], Cross et al. [2407.18393]) rely on ancilla systems appended to the original LDPC code.