The London Institute’s papers are the official record of our discoveries. They allow others to build on and apply our work. Each one is the result of many months of research, so we strive to make them clear, inspiring and beautiful, and publish them in leading journals.

Phase Transitions in Neural Networks Pruning
Statistical physics

An AI phase change

Weight pruning uncovers critical behaviour in deep neural networks with a sharp transition from functional cooperation to disordered failure.

YHYang-Hui HeGCGuido CaldarelliDP
ArXiv
Image for the paper "The role of complexity for digital twins of cities"
Complex systems

Complex digital cities

A complexity-science approach to digital twins of cities views them as self-organising phenomena, instead of machines or logistic systems.

GCGuido CaldarelliEAMBMBCGDHSM..
Nature Computational Science
Image for the paper "Laplacian renormalization group for heterogeneous networks"
Statistical physics

Network renormalization

Applying diffusion-based graph operators to complex networks identifies the proper spatiotemporal scales by overcoming small-world effects.

GCGuido CaldarelliPVTGAG
Nature Physics
Image for the paper "Emergent spatial patterns of coexistence in species-rich plant communities"
Statistical physics

Coexistence in diverse ecosystems

Scale-invariant plant clusters explain the ability for a diverse range of plant species to coexist in ecosystems such as Barra Colorado.

GCGuido CaldarelliPVTG
Physical Review E
Network theory

Physics of financial networks

Statistical physics contributes to new models and metrics for the study of financial network structure, dynamics, stability and instability.

MBPBGCSBFCGCDG..
Nature Reviews Physics
Financial risk

Risky bank interactions

Networks where risky banks are mostly exposed to other risky banks have higher levels of systemic risk than those with stable bank interactions.

GCSKHŠVZ
Physical Review E
Network theory

True scale-free networks

The underlying scale invariance properties of naturally occurring networks are often clouded by finite-size effects due to the sample data.

GCM.GCAMARS.JB
Proceedings of the National Academy of Sciences of the USA
Financial markets

Network valuation in finance

Consistent valuation of interbank claims within an interconnected financial system can be found with a recursive update of banks' equities.

PBMBGCFCMDGVSB
Mathematical Finance
Statistical physics

Physics of networks

Statistical physics harnesses links between maximum entropy and information theory to capture null model and real-world network features.

GCGCTSFSDGAG
Nature Reviews Physics
Complex networks

Information asymmetry

Network users who have access to the network’s most informative node, as quantified by a novel index, the InfoRank, have a competitive edge.

PBGCTS
Journal of Statistical Physics
Financial networks

From ecology to finance

Bipartite networks model the structures of ecological and economic real-world systems, enabling hypothesis testing and crisis forecasting.

GCMSTSFS
Journal of Statistical Physics
Mathematical medicine

Bayesian analysis of medical data

Bayesian networks describe the evolution of orthodontic features on patients receiving treatment versus no treatment for malocclusion.

GCMSPALF
Scientific Reports
Financial markets

Financial network reconstruction

Statistical mechanics concepts reconstruct connections between financial institutions and the stock market, despite limited data disclosure.

GCTSGC
Physical Review E
Financial networks

Bipartite trade network

A new algorithm unveils complicated structures in the bipartite mapping between countries and products of the international trade network.

GCMSFS
Physical Review E
Network theory

Debunking in a world of tribes

When people operate in echo chambers, they focus on information adhering to their system of beliefs. Debunking them is harder than it seems.

GCFZABMVLSSHWQ
PLoS ONE
Financial risk

Pathways towards instability

Processes believed to stabilize financial markets can drive them towards instability by creating cyclical structures that amplify distress.

MBGCSBFC
Nature Communications
Complex networks, Financial risk

Non-linear distress propagation

Non-linear models of distress propagation in financial networks characterise key regimes where shocks are either amplified or suppressed.

MBGCFCJPGV
PLoS ONE
Financial risk

Immunisation of systemic risk

Targeted immunisation policies limit distress propagation and prevent system-wide crises in financial networks according to sandpile models.

ASGCVZGD
Journal de Physique IV
Financial risk

The price of complexity

Increasing the complexity of the network of contracts between financial institutions decreases the accuracy of estimating systemic risk.

GCSBRMTRJS
Proceedings of the National Academy of Sciences of the USA
Network theory

Cascades in flow networks

Coupled distribution grids are more vulnerable to a cascading systemic failure but they have larger safe regions within their networks.

ASGCPLGD
Physica D
Percolation theory

Self-organising adaptive networks

An adaptive network of oscillators in fragmented and incoherent states can re-organise itself into connected and synchronized states.

GCYESB
Scientific Reports
Financial markets

News sentiment and price dynamics

News sentiment analysis and web browsing data are unilluminating alone, but inspected together, predict fluctuations in stock prices.

GCGRIBGBFLMT
PLoS ONE
Network theory

Communities in networks

A new tool derived from information theory quantitatively identifies trees, hierarchies and community structures within complex networks.

GCJPCT
Physical Review E
Financial markets

Effect of Twitter on stock prices

When the number of tweets about an event peaks, the sentiment of those tweets correlates strongly with abnormal stock market returns.

GCGRDAMGIM
PLoS ONE
Complex networks

Democracy in networks

Analysis of the hyperbolicity of real-world networks distinguishes between those which are aristocratic and those which are democratic.

GCMBAC
Physical Review E
Complex networks

Collective attention to politics

Tweet volume is a good indicator of political parties' success in elections when considered over an optimal time window so as to minimise noise.

GCYEMPJSIM
PLoS ONE
Financial risk

DebtRank and shock propagation

A dynamical microscopic theory of instability for financial networks reformulates the DebtRank algorithm in terms of basic accounting principles.

MBGCSBFC
PLoS ONE
Financial risk, Network theory

Fragility of the interbank network

The speed of a financial crisis outbreak sets the maximum delay before intervention by central authorities is no longer effective.

GCMSGC
Network Theory of Finance
Financial risk

Networks of credit default swaps

Time series data from networks of credit default swaps display no early warnings of financial crises without additional macroeconomic indicators.

GCMPSB
Scientific Reports
Network theory

Self-healing complex networks

The interplay between redundancies and smart reconfiguration protocols can improve the resilience of networked infrastructures to failures.

GCASWQ
PLoS ONE
Financial risk

Default cascades in networks

The optimal architecture of a financial system is only dependent on its topology when the market is illiquid, and no topology is always superior.

GCTRHBHPSB
Scientific Reports
Economic complexity

Metrics for global competitiveness

A new non-monetary metric captures diversification, a dominant effect on the globalised market, and the effective complexity of products.

GCLPATMCAG
Journal of Economic Dynamics and Control
Economic complexity

Measuring the intangibles

Coupled non-linear maps extract information about the competitiveness of countries to the complexity of their products from trade data.

GCLPMCAGAT
PLoS ONE
Network theory

The temperature of networks

A new concept, graph temperature, enables the prediction of distinct topological properties of real-world networks simultaneously.

TFGCDGSA
Entropy
Network theory

Scales in weighted networks

Information theory fixes weighted networks’ degeneracy issues with a generalisation of binary graphs and an optimal scale of link intensities.

TFGCDGSA
Social Informatics
Financial networks

Interbank controllability

Complex networks detect the driver institutions of an interbank market and ascertain that intervention policies should be time-scale dependent.

GCDDSBMRGGFP
Scientific Reports
Financial networks

Reconstructing credit

New mathematical tools can help infer financial networks from partial data to understand the propagation of distress through the network.

GCACFPAGMP
Nature Physics
Financial networks

Complex derivatives

Network-based metrics to assess systemic risk and the importance of financial institutions can help tame the financial derivatives market.

GCSBCGRMJS
Nature Physics
Financial risk

Bootstrapping topology and risk

Information about 10% of the links in a complex network is sufficient to reconstruct its main features and resilience with the fitness model.

GCNMSBMPAG
Journal of Statistical Physics
Network theory

Weighted network evolution

A statistical procedure identifies dominant edges within weighted networks to determine whether a network has reached its steady state.

GCACICFP
Physical Review E
Economic complexity

Network analysis of export flows

Network theory finds unexpected interactions between the number of products a country produces and the number of countries producing each product.

GCLPASMCAGAT
PLoS ONE
Economic complexity

Metric for fitness and complexity

A quantitative assessment of the non-monetary advantage of diversification represents a country’s hidden potential for development and growth.

GCLPATMCAG
Scientific Reports
Mathematical medicine

Networks for medical data

Network analysis of diagnostic data identifies combinations of the key factors which cause Class III malocclusion and how they evolve over time.

ASGCPAMSJMLF
PLoS ONE
Financial markets

Search queries predict stocks

Analysis of web search queries about a given stock, from the seemingly uncoordinated activity of many users, can anticipate the trading peak.

GCIBSBMCAUIW
PLoS ONE
Network theory

Robust and assortative

Spectral analysis shows that disassortative networks exhibit a higher epidemiological threshold and are therefore easier to immunize.

ASGCGDVZ
EPL
Network theory

Clustering inverted

Edge multiplicity—the number of triangles attached to edges—is a powerful analytic tool to understand and generalize network properties.

GCVZDG
EPL