Entanglement Complexity Research Articles

Rorty, Science Studies, and the Politics of Post-Truth

Abstract In a symposium built around a critical reassessment by Nicholas Gaskill of Richard Rorty's pragmatism, this contribution examines the provocative question of whether Rorty's rhetoric hinders Rortian aims. When reconsidering him in company with “the philosophical wing of science studies” (Bruno Latour, Isabelle Stengers, and Donna Haraway), Gaskill finds that Rorty's persistent assumption of nature/culture and word/world dichotomies is politically dangerous and prevents his comprehending both distributed agency and the complexity of human entanglements with the nonhuman. Gaskill's Rorty lacks a sustained and coherent positive project, but a fuller picture, outlined in this article, reveals not only greater alignment of Rorty with science studies and agential realism but also key Rortian contributions to those fields that are particularly of moment in our “post-truth” condition.

Entanglement of random hypergraph states

Random quantum states and operations are of fundamental and practical interests. In this paper, we investigate the entanglement properties of random hypergraph states, which generalize the notion of graph states by applying generalized controlled-phase gates on an initial reference product state. In particular, we study the two ensembles generated by random controlled-Z (CZ) and controlled-controlled-Z (CCZ) gates, respectively. By applying tensor network representation and combinational counting, we analytically show that the average subsystem purity and entanglement entropy for the two ensembles feature the same volume law but greatly differ in typicality, namely, the purity fluctuation is small and universal for the CCZ ensemble while it is large for the CZ ensemble. We discuss the implications of these results for the onset of entanglement complexity and quantum chaos.

Probing the entanglement of operator growth

Abstract In this work we probe the operator growth for systems with Lie symmetry using tools from quantum information. Namely, we investigate the Krylov complexity, entanglement negativity, entanglement entropy, and capacity of entanglement for systems with SU(1,1) and SU(2) symmetry. Our main tools are two-mode coherent states, whose properties allow us to study the operator growth and its entanglement structure for any system in a discrete series representation of the groups under consideration. Our results verify that the quantities of interest exhibit certain universal features in agreement with the universal operator growth hypothesis. Moreover, we illustrate the utility of this approach relying on symmetry as it significantly facilitates the calculation of quantities probing operator growth. In particular, we argue that the use of the Lanczos algorithm, which has been the most important tool in the study of operator growth so far, can be circumvented and all the essential information can be extracted directly from symmetry arguments.

Finite-Function-Encoding Quantum States

We introduce finite-function-encoding (FFE) states which encode arbitrary d-valued logic functions, i.e., multivariate functions over the ring of integers modulo d, and investigate some of their structural properties. We also point out some differences between polynomial and non-polynomial function encoding states: The former can be associated to graphical objects, that we dub tensor-edge hypergraphs (TEH), which are a generalization of hypergraphs with a tensor attached to each hyperedge encoding the coefficients of the different monomials. To complete the framework, we also introduce a notion of finite-function-encoding Pauli (FP) operators, which correspond to elements of what is known as the generalized symmetric group in mathematics. First, using this machinery, we study the stabilizer group associated to FFE states and observe how qudit hypergraph states introduced in Ref. \cite{2017PhRvA..95e2340S} admit stabilizers of a particularly simpler form. Afterwards, we investigate the classification of FFE states under local unitaries (LU), and, after showing the complexity of this problem, we focus on the case of bipartite states and especially on the classification under local FP operations (LFP). We find all LU and LFP classes for two qutrits and two ququarts and study several other special classes, pointing out the relation between maximally entangled FFE states and complex Butson-type Hadamard matrices. Our investigation showcases also the relation between the properties of FFE states, especially their LU classification, and the theory of finite rings over the integers.

From tree tensor network to multiscale entanglement renormalization ansatz

Tensor network states (TNSs) offer an efficient representation for the ground state of quantum many-body systems and play an important role in the simulations of them. Numerous TNSs have been proposed in the past few decades. However, due to the high cost of TNS for two-dimensional systems, a balance between the encoded entanglement and computational complexity of TNS is yet to be reached. In this work we introduce a new tree tensor network-based (TTN-based) TNS dubbed a ``fully augmented tree tensor network (FATTN) by releasing the constraint in augmented tree tensor network (ATTN). When disentanglers are augmented in the physical layer of TTN, FATTN can provide more entanglement than TTN and ATTN. At the same time, FATTN maintains the scaling of computational cost with bond dimension in TTN and ATTN. Benchmark results on the ground-state energy for the transverse Ising model are provided to demonstrate the improvement of accuracy of FATTN over TTN and ATTN. Moreover, FATTN is quite flexible, which can be constructed as an interpolation between TTN and the multiscale entanglement renormalization ansatz to reach a balance between the encoded entanglement and the computational cost.

Genuine N-partite entanglement and distributed relationships in the background of dilation black holes

With the complexity of information tasks, the bipartite and tripartite entanglement can no longer meet our needs, and we need more entangled particles to process relativistic quantum information. In this paper, we study the genuine N-partite entanglement and distributed relationships for Dirac fields in the background of dilaton black holes. We present the general analytical expression including all physically accessible and inaccessible entanglement in curved spacetime. We find that the accessible N-partite entanglement exhibits irreversible decoherence as the increase of black hole’s dilaton, and on the other hand the inaccessible N-partite entanglement increases from zero monotonically or non-monotonically, depending on the relative numbers of the accessible to the inaccessible modes, which forms a sharp contrast with the cases of bipartite and tripartite entanglement where the inaccessible entanglement increase only monotonically. We also find two distributed relationships between accessible and inaccessible N-partite entanglement in curved spacetime. The results give us a new understanding of the Hawking radiation.

Everyday mobility practices and the ethics of care: young women’s reflections on social responsibility in the time of COVID-19 in three African cities

This paper draws principally from COVID-19 diaries written by young women whom we had previously trained as peer researchers in a mobility study of low-income neighbourhoods in Abuja, Cape Town and Tunis. Some live with parents or older extended family members, others have children in their care, but concerns around avoiding contagion have forced all peer researchers to reflect on their everyday socio-spatial mobility practices. This includes whether/how much they need to travel or can substitute virtual for physical travel; which transport mode to take and when; what precautions they must take on the move; what strategies of engagement are required to cope with externally imposed rules and contingencies – and the potential impact of their negotiations, decisions and experiences on the health of those dear to them at home. Reflections on these pandemic-induced responsibilities range from social distancing and mask wearing to issues around handling cash, modes of greeting and travel to funerals. The personal interpretations of responsibility that are reported in individual diaries point to the complexity of entanglements between everyday mobility practices on city streets and negotiated relations of care within the household (and other relational settings) that have emerged and deepened as the COVID story unfolds.

Transitions in entanglement complexity in random quantum circuits by measurements

Random Clifford circuits doped with non Clifford gates exhibit transitions to universal entanglement spectrum statistics [1] and quantum chaotic behavior. In [2] we proved that the injection of Ω(n) non Clifford gates into a n-qubit Clifford circuit drives the transition towards the universal value of the purity fluctuations. In this paper, we show that doping a Clifford circuit with Ω(n) single qubit non Clifford measurements is both necessary and sufficient to drive the transition to universal fluctuations of the purity.

Effective Immunosurveillance After Allogeneic Hematopoietic Stem Cell Transplantation in Acute Myeloid Leukemia.

The number of patients receiving allogeneic hematopoietic stem cell transplantation (alloHCT) has increased constantly over the last years due to advances in transplant technology development, supportive care, transplant safety, and donor availability. Currently, acute myeloid leukemia (AML) is the most frequent indication for alloHCT. However, disease relapse remains the main cause of therapy failure. Therefore, concepts of maintaining and, if necessary, reinforcing a strong graft-versus-leukemia (GvL) effect is crucial for the prognosis and long-term survival of the patients. Over the last decades, it has become evident that effective immunosurveillance after alloHCT is an entangled complex of donor-specific characteristics, leukemia-associated geno- and phenotypes, and acquired resistance mechanisms. Furthermore, adoption of effector cells such as natural killer (NK) cells, alloreactive and regulatory T-cells with their accompanying receptor repertoire, and cell–cell interactions driven by messenger molecules within the stem cell and the bone marrow niche have important impact. In this review of pre- and posttransplant elements and mechanisms of immunosurveillance, we highlight the most important mechanisms after alloHCT.

Holographic entanglement entropy and complexity of microstate geometries

We study holographic entanglement entropy and holographic complexity in a two-charge, frac{1}{4} -BPS family of solutions of type IIB supergravity, controlled by one dimensionless parameter. All the geometries in this family are asymptotically AdS3×\U0001d54a3×\U0001d54b4 and, varying the parameter that controls them, they interpolate between the global AdS3× \U0001d54a3× \U0001d54b4 and the massless BTZ3× \U0001d54a3× \U0001d54b4 geometry. Due to AdS/CFT duality, these geometries are dual to pure CFT heavy states.We find that there is no emergence of entanglement shadow for all the values of the parameter and we discuss the relation with the massless BTZ result, underlying the relevance of the nature of the dual states.We also compute the holographic complexity of formation of these geometries, finding a nice monotonic function that interpolates between the pure AdS3 result and the massless BTZ one.

Effect of back reaction on entanglement and subregion volume complexity in strongly coupled plasma

The back reaction imparted by a uniform distribution of heavy static fundamental quarks on large Nc strongly coupled gauge theory can be holographically realized as a deformation in AdS blackhole background. The presence of back reaction brings significant changes in to the entanglement structure of the strongly coupled boundary theory at finite temperature. Since the deformed blackhole geometry still remains asymptotically AdS, the gauge/ gravity duality allows us to explore the entanglement structure of back reacted plasma in a quantitative way by computing various measures, e.g holographic en­ tanglement entropy (HEE) and entanglement wedge cross section (EWCS). We explicitly study the variation of those entanglement measures with respect to the uniform density of heavy static fundamental quarks present in the boundary theory. In particular, we notice enhancement of both HEE and EWCS with respect to quark density. We also study the effect of back reaction on the holographic subregion volume complexity. In this analysis we observe an occurrence of logarithmic divergence proportional to the quark density parameter.

Translocation of links through a pore: effects of link complexity and size

We have used Langevin dynamics to simulate the forced translocation of linked polymer rings through a narrow pore. For fixed size (i.e. fixed number of monomers) the translocation time depends on the link type and on whether the rings are knotted or unknotted. For links with two unknotted rings the crossings between the rings can slow down the translocation and are responsible for a delay as the crossings pass through the pore. The results fall on a set of relatively smooth curves for different link families with the translocation time not always increasing with crossing number within the same family. When one ring is knotted the results depend on whether the link is prime or composite and, for the composite case, they depend on whether the knotted or unknotted ring enters the pore first. We find a similar situation for 3-component links where the results depend on whether the link is prime or composite. These results contribute to our understanding of how the entanglement complexity between filaments impacts their translocation dynamics and should be useful for extending nanopore-sensing techniques to probe the topological properties of these systems.

Control of Surface Density of Textile Materials Using Automated Scanning System

The paper demonstrates the importance of controlling the surface density of textiles, which include mainly fabrics, knitted fabrics and nonwoven fabrics, in order to improve the quality of their manufacture.
 It considers the most accurate methods of controlling surface density by determining the mass to area ratio of the textile sample. And it is also shown that, in addition to high accuracy, such met­hods have many fundamental disadvantages: the need to obtain a sample of textile material, low productivity, inability to automate the process of determining surface density, and so on.
 In addition, it deals with optical methods for controlling surface density based on the imaging of textile material and its subsequent analysis. However, the presence of factors such as entanglement complexity, the presence of pores, and some others does not fully reveal the potential of optical surface density methods.
 The paper also shows that at different points in the surface of the textile material, its surface density may differ significantly from its average value. Therefore, there is a need for an automated scanning system that allows radiating and receiving electroacoustic converters to be moved to exactly the point of the surface of the textile material whose surface density requires measurement.
 In order to solve the problem, it was proposed to use a toothed belt gear, and to drive it with the help of step motors controlled through drivers. In turn, to communicate drivers with the control computer, it was proposed to use a microcontroller with an integrated USB interface (for example, manufactured by Microchip Technology Inc.), and software for it to write in one of the high-
 level programming languages (for example, C #).
 This construction of the automated scanning system is due to the fact that the existing means of linear movement, in terms of the design of the scanning system, have a lot of redundancy: too much cost, too much accuracy, the need to use specialized software, and so on.
 The use of the proposed linear positioning means will allow the scanning system to have sufficiently high metrological characteristics at a relatively low cost.

Holographic entanglement entropy and complexity in Stückelberg superconductor

The holographic superconductors, as one of the most important application of gauge/gravity duality, promote the study of strongly coupled superconductors via classical general relativity living in one higher dimension. One of the interesting properties in holographic superconductor is the appearance of first and second order phase transitions. Recently, another active studies in holographic framework is the holographic entanglement entropy and complexity evaluated from gravity side. In this note, we study the properties of the holographic entanglement entropy and complexity crossing both first and second order phase transitions in Stückelberg superconductor. We find that they behave differently in two types of phase transitions. We argue that holographic entanglement entropy and complexity conjectured with the volume can also be a possible probe to the type of superconducting phase transition.

Entanglement entropy and complexity of singular subregions in deformed CFT

In the framework of the AdS/CFT correspondence, imposing a scalar field in the bulk space-time leads to deform the corresponding CFT in the boundary, which may produce corrections to entanglement entropy, as well as the so-called subregion complexity. We have computed such corrections for a set of singular subregions including kink, cones and creases in different dimensions. Our calculations shows new singular terms including universal logarithmic corrections for entanglement entropy and subregion complexity for some distinct values of conformal weight.

The Rabl configuration limits topological entanglement of chromosomes in budding yeast

The three dimensional organization of genomes remains mostly unknown due to their high degree of condensation. Biophysical studies predict that condensation promotes the topological entanglement of chromatin fibers and the inhibition of function. How organisms balance between functionally active genomes and a high degree of condensation remains to be determined. Here we hypothesize that the Rabl configuration, characterized by the attachment of centromeres and telomeres to the nuclear envelope, helps to reduce the topological entanglement of chromosomes. To test this hypothesis we developed a novel method to quantify chromosome entanglement complexity in 3D reconstructions obtained from Chromosome Conformation Capture (CCC) data. Applying this method to published data of the yeast genome, we show that computational models implementing the attachment of telomeres or centromeres alone are not sufficient to obtain the reduced entanglement complexity observed in 3D reconstructions. It is only when the centromeres and telomeres are attached to the nuclear envelope (i.e. the Rabl configuration) that the complexity of entanglement of the genome is comparable to that of the 3D reconstructions. We therefore suggest that the Rabl configuration is an essential player in the simplification of the entanglement of chromatin fibers.

Holographic subregion complexity from kinematic space

We consider the computation of volumes contained in a spatial slice of AdS3 in terms of observables in a dual CFT. Our main tool is kinematic space, defined either from the bulk perspective as the space of oriented bulk geodesics, or from the CFT perspective as the space of entangling intervals. We give an explicit formula for the volume of a general region in a spatial slice of AdS3 as an integral over kinematic space. For the region lying below a geodesic, we show how to write this volume purely in terms of entangling entropies in the dual CFT. This expression is perhaps most interesting in light of the complexity = volume proposal, which posits that complexity of holographic quantum states is computed by bulk volumes. An extension of this idea proposes that the holographic subregion complexity of an interval, defined as the volume under its Ryu-Takayanagi surface, is a measure of the complexity of the corresponding reduced density matrix. If this is true, our results give an explicit relationship between entanglement and subregion complexity in CFT, at least in the vacuum. We further extend many of our results to conical defect and BTZ black hole geometries.

Holographic entanglement entropy, complexity, fidelity susceptibility and hierarchical UV/IR mixing problem in AdS2/open strings

In this paper, we will compute the holographic complexity (dual to a volume in AdS), holographic fidelity susceptibility and the holographic entanglement entropy (dual to an area in AdS) in a two-dimensional version of AdS which is dual to open strings. We will explicitly demonstrate that these quantities are well defined, and then argue that a relation for fidelity susceptibility and time should hold in general due to the AdS2 version of the classical Kepler’s principle. We will demonstrate that it holds for AdS2 solution as well as conformal copies metrics in bulk theory of a prescribed dual conformal invariant quantum mechanics which have been obtained in open string theory. We will also show that hierarchical UV/IR mixing exists in boundary string theory through the holographic bulk picture.

Quantum state concentration and classification of multipartite entanglement

Entanglement is a unique nature of quantum theory and has tremendous potential for application. Nevertheless, the complexity of quantum entanglement grows exponentially with an increase in the number of entangled particles. Here we introduce a quantum state concentration scheme which decomposes the multipartite entangled state into a set of bipartite and tripartite entangled states. It is shown that the complexity of the entanglement induced by the large number of particles is transformed into the high dimensions of bipartite and tripartite entangled states for pure quantum systems. The results not only simplify the tedious work of verifying the (in)equivalence of multipartite entangled states, but also are instructive to the quantum many-body problem involving multipartite entanglement.

The European Bauman

The European Bauman